AH
AH
CH

AH形
照光式押しボタンスイッチ
１桁ユニット式表示器＋スイッチ機能
AH Illuminated Pushbutton Switch
形・スーパーCH形
Slim
and characteristic size.
スリムな長四角形状
光式押しボタンスイッチ

Easy
to use as an indicator,■本体奥行き16mmの短胴構造。
体奥行16mmの短胴構造ながら
also
available a flat type with a low button.
■ボタン形状はスリムな7.8×23.1長四角。
面照光、2分割照光、2色発光を実現。
■フラット表示灯タイプも用意。

■ Depth behind panel：Only 16 mm
奥行：16mmの短胴構造です。コネクタタイプは23mm。
■ LED Full-Face, Dual-Color illumination available.
部■ Terminal：Solderingの照光方式は全面単色、全面2色、2分割照光を実現。保護抵抗は内蔵で照光部はパネル前面より交換可能です。
ン形状は13.2角、13.2×19.4長四角ボタンと本体、照光部同一サイズのント基板専用の16角ボタンの3種類があります。
角、13.2×19.4長四角ボタンには操作性のよいディンプルボタンも用意した。
NC

Switchッチ部
connection C
ルスプリングを使ったマイクロスイッチ機構を採用．長寿命，軽快なタNO感、高信頼性が得られます。

セサリー
製品URL
取付用バリヤー、ガードカバー、ソケット、マトリックス取付金具。

接触形式

NC
C
NO

製品QRコードh p://www.sunmulon.co.jp/sun/products/display_j/ad.html
CHARACTERISTICS

製

品

仕

Button Size

様

Rectangle：7.8×23.1 mm

NC

C

Cross-bar contact

弊社ホームページからPDF，DXF，3D 等 各種データがダウンロード出来ます。
接触形式
Silver contact (Gold-plated)
Contact Material
Rating(Resistive Load)
製品仕様一覧

AC 125NO
V 0.1 ADC 30 V 0.1 A

AC 125 V 3 A
AC 250 V 3 A

Insulation Resistance

製

Dielectric Strength

品

仕More than 100 MΩ at DC 500 V様

AC 600 V RMS between NC and NO terminal
AC 1500 V RMS between terminals and ground50/60 Hz for 60 sec. at normal ambient temperature and humidity

Less than 50 mΩ (Initial value)at DC 6 V 1 A

Contact ResistanceLess than 50 mΩ (Initial value)at DC 6 V 0.1 A

Vibration Resistance

10 to 55 Hz, Amplitude 1.5 mm

Mechanical Life

More than 1,000,000 operations

MomentaryMore thanブロック図
30,000 operations at max. rated load

Electrical Life (Resistive Load)
Operating Force

1.96 N

Total Travel

2.5 mm max.

Weightmax.

5g－15℃ to 50℃（No Freeze, No Condensation）

Ambient Operating Temperature

80%RH max. （No Condensation）

Ambient Operating Humidity
Ambient Storage Temperature－25℃ to 65℃（No Freeze, No Condensation）

Ambient Storage Humidity

80%RH max. （No Condensation）

製品URL
http://www.sunmulon.co.jp/sun/products/switch_j/ ah.html

製品QRコード

弊社ホームページからPDF，DXF，3D 等各種データがダウンロード出来ます。

https://www.sunmulon.co.jp/english/products/switch_e/ah.html◇Dimensions：page AH-3
◇LED specifications：page AH-7

◇Ordering code：page AH-4～5◇Terminals：page AH-8

Sunmulon Co., Ltd.

SunmulonCo., Ltd.
Ltd.
Sunmulon
Co.,
Sunmulon Co.,Ltd.

◇Internal connection arrangements：page AH-6
◇Mounting design / Panel cutout：page AH-8

AD-1
AH-1

SPECIFICATIONS
Full-Face

SPDT

Terminal

Soldering

RoHS (10 Substances)● Silver contact (Gold-plated)A

Illumination
Dual-Color
type
Non-illumination
Contact

CONTACT RATINGS

A
AAA
Conform to standards

A : Applicable

Voltage

Current (A)(Resistive load)

AC 125 V
250 V

3
3

DC

2

8V
14 V
30 V
125 V

2
1
0.3

● Cross-bar contact
Rating

AC 125 V 0.1 A (Resistive load)
DC 30 V 0.1 A (Resistive load)

STRUCTURE

BUTTONFILTER

HOUSINGILLUMINATION TYPES
LED color symbol

70

Red

80 Green

90 Yellow※ Yellow (90) is actually “ORANGE Yellow” not Lemon Yellow.

Full-Face

70

80

90

Dual-Color

70・80

80・90

90・70

Sunmulon Co., Ltd.

AH-2

DIMENSIONS● With Flange
Rectangle

12

23.1

7.8
2.5

28

16

20.5

2

Sunmulon markTOP VIEW
0.25

3D

0.5

10

26

DXF

Flat Indicator

28

12

23.1

7.8

16

20.5

2 0.3

Sunmulon markTOP VIEW
0.25

3D

10
26

DXF

ACCESSORIES
Name

Appearance

Classification

Part no.

Precautions for use

For removal button

SJ-0001- Be used to remove button from housing.

For removal flat indicator

SJ-0009- Be used to remove button of flat indicatorfrom housing.

Removing tool

009

SJ-0

3D・DXF data download site ： https://www.sunmulon.co.jp/download/

Tolerance : ± 0.4 mm

Sunmulon Co., Ltd.

AH-3

ORDERING CODE 【Full-Face】
Assembled Part

AH

W0

S

● OPERATION● LED CIRCUIT

L

Indicator

D Full- FaceF

Flat Indicator

X Without LED

M Momentary● Supply Voltage to LED

Flat indicator button level is Flat. (Locked position)

1 DC 5V Built-in resistor
2 DC12V Built-in resistor● CONTACT
0 Indicator● TERMINAL

3 SPDT・Silver (Gold-Plated)S

5 SPDT・Crossbar● FILTER COLOR

W0 Rectangle● BUTTON COLOR

70 Red80 Green※2）

90 Yellow※1）

X

Without LED

4 DC 5V Non-resistor
5 DC12V Non-resistor
6 DC24V Non-resistor● BUTTON SHAPE● LED COLOR

Soldering

3 DC24V Built-in resistor

R

Red

G

Green

O

Yellow※1）

Y

Lemon Yellow※2）

M

Milk-white

C

Clear

X

Without button ※3）● HOUSING
COLOR
K

Black

H

Gray

1

Red

2

Green

3

Yellow

4

Milk-white

X Without LED
For Non-resistor type,use external protective resistor.

※1）

8

Lemon Yellow ※2）

X

Without filter※3）

Generally, in case of using color button,
filter is not necessary.

● NOTES※1) The color of “Yellow” for LED (90), button (O) and filter (3) is actually “Orange Yellow” not Lemon Yellow.
※2) When using Lemon Yellow button (Y) and filter (8), specify LED color Green (80).
※3) For without button (X), specify without filter (X).

◇Dimensions：page AH-3
◇LED specifications：page AH-7

◇Internal connection arrangements：page AH-6
◇Terminals：page AH-8
◇Mounting design / Panel cutout：page AH-8

SunmulonCo., Ltd.
Ltd.
Sunmulon Co.,

AH-4

ORDERING CODE 【Dual-Color】
Assembled Part

AH

W3 1 2

S● LED CIRCUIT● OPERATION
L

Indicator

F

Flat Indicator

A Dual-Color Anode common（＋）

K Dual-Color Cathode common（－）

M Momentary
Flat indicator button level is Flat. (Locked position)● Supply Voltage to LED
1 DC 5V Built-in resistor● CONTACT2 DC12V Built-in resistor

0 Indicator

3 DC24V Built-in resistor

3 SPDT・Silver (Gold-Plated)
5 SPDT・Crossbar

5 DC12V Non-resistor● BUTTON SHAPE

6 DC24V Non-resistor● LED COLOR
80 Green
90 Yellow※3)

For Non-resistor type,use external protective resistor.

W3 Rectangle

70 Red※3)

4 DC 5V Non-resistor● TERMINAL
Put the color numbers into frame 1, 2.

S(Dual-Color combination)
7080・8090・9070

Soldering● FILTER COLOR ※2)

Yellow (90) is actually “ORANGE Yellow” not Lemon Yellow.

● BUTTON COLOR ※2)
C

Clear

M

Milk-white

X

Without button

4

Milk-white

X

Without filter※1)● HOUSING
COLOR

※1)

K

Black

H

Gray

● NOTES※1) For without button (X), specify without filter (X).

※2) Button should be C (Clear) with Milk-white filter (4) or M (Milk-white) without filter (X).
※3) Simultaneous lighting is not possible for DC24V Built-in resistor type (3).
Please select DC24V Non-resistor type (6) and apply required external resistor for simultaneous lighting.

◇Dimensions：page AH-3
◇LED specifications：page AH-7

◇Internal connection arrangements：page AH-6
◇Terminals：page AH-8
◇Mounting design / Panel cutout：page AH-8

SunmulonCo., Ltd.
Ltd.
Sunmulon Co.,

AH-5

REPLACEMENT PARTS● Full-Face BUTTON／FILTER
Red

Green

Yellow

Lemon Yellow

Milk-white

Clear

BUTTON

AH-2708-1LR AH-2708-1LG AH-2708-1LO AH-2708-1LY AH-2708-1LM AH-2708-2CC

FILTER

AH-2709-LR AH-2709-LG

AH-2709-LO AH-2709-LY

AH-2709-LM● Dual-Color BUTTON／FILTER
Milk-white

Clear

BUTTON

AH-2708-1LM AH-2708-2CC

FILTER

AH-2709-LM

FILTER DIMENSIONS
6.4

21.4

2

LEGEND FACE

AH-2709

CONCAVE FACE

INTERNAL CONNECTION ARRANGEMENTS● Full-Face
Voltage
BOTTOM VIEW

DC5V

TOP VIEW
Sunmulon mark

L1

※These are all internal connection diagrams for built-in resistor type.
※For Non-resistor type, the resistor part in the diagram should beshort- circuited.

LC

Sunmulon mark

DC12V
DC24V

L1

LC

● Dual-Color
BOTTOM VIEW

DC5V

Cathode common

Anode common

Voltage

L1

TOP VIEW
Sunmulon mark

DC24V

L1

LC

LC

L2

L2

Sunmulon markSunmulon mark

DC12V

L1

LC

LC

L2

Sunmulon mark

L1
L2

● Dual-Color combination (Common for each voltage)
Terminals

LC1-L1
LC1-L2

LED Color

Red
Green

Green Yellow
Yellow Red
Tolerance : ± 0.4 mm

Sunmulon
SunmulonCo.,
Co.,Ltd.
Ltd.

AH-6

LED SPECIFICATIONS 【Full-Face】● BUILT-IN RESISTOR
Voltage
DC 5V
DC 12VDC 24V

±5%

±5%
±5%

Rated Current (mA)
Red

Green

Yellow

30

30

30

15

15

15

10

10

10

● Wiring Diagram● NON-RESISTOR (EXTERNAL RESISTOR)
DC5 V

Supply Voltage
LED Color

Red

Green Yellow

Max. Forward Current IFM （mA） 40
DC Reverse Voltage

VR （V） 10

Forward Voltage【IF=20mA】
V F（Typ.）（V）

DC12V・24V

4

Derating (Operating temperature)

Red

Green Yellow

40

40

20

20

20

10

10

20

20

20

4.2

4

8

8.4

8

0.36

(over 25℃ working temperature)（mA/℃）

IF

R
VDD

VF

Refer to the following formula
to calculate external resistance values.

0.36

Pulse Width PW （μs）
Pulse
Lighting Duty Ratio DR
Allowable forward current IFP
（mA）

100
10 －1
100

R＝

VDD ：Supply Voltage
VF ：Forward Voltage
IF ：Forward Current

VDD－V FIFIF (Forward Current) :Refer to the Rated Current of BUILT-IN RESISTOR type,and be sure to set less than IFM (Max. Forward Current).

LED SPECIFICATIONS 【Dual-Color】● BUILT-IN RESISTOR
Voltage
DC 5V
DC 12VDC 24V

±5%

±5%
±5%

Rated Current (mA)
Red

Green

Yellow

30

30

30

15

15

15

10

10

10

※ DC 24 V Built-in resistor type (3) cannot be lit simultaneous lighting.
For simultaneous lighting, specify DC 24 V Non-resistor type (6)and use external protective resistor.

● Wiring Diagram● NON-RESISTOR (EXTERNAL RESISTOR)
DC5 V

Supply Voltage
LED ColorRed

Max. Forward Current IFM （mA） 40

DC12V・24V

Green Yellow

Red

Green Yellow

40

40

20

20

20

DC Reverse Voltage

VR （V） 10

10

10

20

20

20

Forward Voltage【IF=20mA】
V F（Typ.）

（V）

4

4.2

4

8

8.4

8

Derating (Operating temperature)(over 25℃ working temperature)（mA/℃）
Pulse Width PW （μs）
Pulse
Lighting Duty Ratio DR
Allowable forward current IFP
（mA）

0.36

0.36
100
10 －1
100

VDD

VF

VDD
IF

R

R

IF

※ The diagram above shows for Anode common.

Refer to the following formula
to calculate external resistance values.

R＝

VDD－V FIFVDD ：Supply Voltage
VF ：Forward Voltage
IF ：Forward Current

IF (Forward Current) :Refer to the Rated Current of BUILT-IN RESISTOR type,and be sure to set less than IFM (Max. Forward Current).

For resistance value calculation
https://www.sunmulon.co.jp/english/products/led.html
The resistance value can be calculated just by entering the items.

Sunmulon Co., Ltd.

AH-7

TERMINALS● TERMINALS LAYOUT (BOTTOM VIEW) (Common to all illumination types)
SPDT

INDICATOR

Sunmulon markSunmulon mark

L1
L2

COM

NO

NC

L2

LC

（BOTTOM VIEW）

Sunmulon markLC

L1 COM

5.08

L1● TERMINALS DIMENSIONS

NO

NC

LC

5.08

5.08

5.08

L2
5.08

2

0.8

4.8

1.6

2.8

4.8

1.6

2.8

TERMINAL SHAPE

0.8

0.25

0.5

2

LC/L1/L2

NC/NO/COM

MOUNTING DESIGN／PANEL CUTOUT
Mounting design

Panel cutout

Individual(Horizontal)
12

Recommended panel thickness : 1 to 3.2 mm

10.5 ＋0.15
－0.1

28

＋0.15
26.5＋28（n－1）
－0.1

12

Multiple(Horizontal)

28nn : Number of Units

Individual(Vertical)

26.5 ＋0.15
－0.1

28

Recommended panel thickness : 1 to 3.2 mm

12Multiple(Vertical)
28

10.5＋12（n－1）＋0.15
－0.1

12n

n : Number of Units※ If the panel is to be finished (e.g. coated), make sure that the panel meets the specified dimensions after the coating.
In case the panel cut dimension is too small, it may cause malfunction.
※ After the panel-cutting process, make sure to remove burrs on the surface.

Tolerance : ± 0.4 mm

Sunmulon Co., Ltd.

AH-8

ASSEMBLY & DISASSEMBLY
2. Fitting Filter

1. Removing Button

Put the filter in the button with the horizontal face down.

Be sure to remove with the removing tool (SJ-0001).
Hang the button with the removing tool in the groove,and pull it straight out.

fook

3. Fitting Button
Align the fooks on both sides of the button,
the groove on the housing,and fit the button until click.

Groove※ In case removing in any other way than the above,it may cause damage to the button.

※ Do not reuse buttons that have been removed and deformed.

PRECAUTIONS FOR CORRECT USE

021.4－0.2
0
6.4 －0.2

1. Solder quickly and correctly at 350℃ max. and for 3 seconds or less.
Be careful not to touch the soldering iron to the main body.
2. Wait for one minute during and after soldering before exerting any external force on the solder.
3. The rated voltage is shown on the side of the housing, so be sure before use.
4. Character films are not included.
If preparing the character film separately, use a heat-resistant film with a thickness of 0.1 mm.
For dimensions, please refer to the figure on the right.
5. LED elements cannot be replaced, so please do not touch them.

※ For handling instructions and precautions other than the above, please refer to “Safety Precautions for All IlluminatedPushbutton Switches”.

Tolerance : ± 0.4 mm
As of July 2023

Sunmulon Co., Ltd.

AH-9

Safety Precautions for All Illuminted Pushbutton Switches
1. Notes on contents of Catalogs(1) Rated values, performance values, and specification values of Sumulon products listed in this catalog are values acquired under respective conditionsin independent testing, and do not guarantee values gained in combined conditions.
(2) The ambient operating temperature(humidity) is guaranteed by evaluation based on characteristics, and does not guarantee continuous use for a long
period of time near the upper or lower limit of the ambient operating temperature(humidity) or permanent use at that temperature(humidity).
(3) Reference data and reference values listed in catalogs are for reference purposes only, and do not guarantee that the product will always operate
appropriately in that range.
(4) The specifications / appearance and accessories of Sunmulon products listed in catalogs are subject to change or termination of sales without notice,for improvemnet or other reasons.
(5) The content of catalogs is subject to change without notice.

2. Note on applications(1) If using Sunmulon products in combination with other products, confirm the following suitability by yourself. Sunmulon shall provide no guarantees
regarding the combination suitability.
(a) Regulations, satndards, or laws to which your machinery, equipment, ect. must conform(b) Functionality and safety of your machinery and equipment(2) Wiring and installation that ensures the Sunmulon product used in your system, machine, device, or the like can perform and function according to
its specifications.
(3) When using Sunmulon products, be cautious when implementing the following.
(a) Use of Sunmulon products with sufficient allowance for rating and performance.
(b) Safety design, including redundant design and malfunction prevention design that prevents other danger and damage even in the event that
Sumulon product fails.
(4) Sunmulon products are designed and manufactured as general-purpose products for general industrial products. They are not intended for use
in the following applications, and in the event that you use Sunmulon product for these applications, unless otherwise agreed upon between you
and Sunmulon, Sunmulon shall provide no guarantees whatsoever regarding Sunmulon products.
(a) Safety devices intended for human body protection(b) Direct control of transport equipmnt (railroads / airplanes / ships / vehicles / vehicle instruments, etc.)(c) Space equipment, submarine equipment(d) Nuclear power control equipment, radiation related equipment(e) Combustion equipment, electric heat equipment(f) Disaster prevention and security equipment(g) Elevating equipment(h) Amusement facilities(i) Facilities subject to government or industry regulations(j) Use in applications that require a high degree of safety, any other equipment, instruments, or the like that could endanger life or human health

3. Warranty(1) The warranty period for Sunmulon products shall be 1 year after purchase or delivery to the specified location.
(2) Warranty scope should a failure occur in Sunmulon product during the above warranty period for reasons attributable to Sunmulon, then Sunmulon shallprovide that product, free of charge, the same quantity. Further, in no event shall liability of Sunmulon exceed the individual price of the product onwhich liability is asserted.
(3) Failures cause by the following reasons shall be deemed outside the scope of this warranty.
(a) The product was handled or used deviating from conditions / environment listed in the catalogs(b) The failure was caused by reasons other than Sunmulon product(c) Modification or repair was performed by a party other than Sunmulon(d) Replacement of maintenance parts, installation of accessories, or the like was not performed properly in accordance with the user’s manual andcatalogs(e) The failure could not have been predicted with the scientific and technical standards at the time when the product was shipped from Sunmulon(f) The failure was due to other causes not attributable to Sunmulon (including cases of force majeure such as natural disasters and other disasters)(4) The warranty listed in this Safety Precautions is the full and complete warranty for Sunmulon products, and Sunmulon shall bear no liability whatsoever
regarding special damages, indirect damages, incidental damages, or passive damages that occurred due to Sunmulon product.

4. Handling precautions for switch(1) Do not perform wiring with power supplied to the switch. Do not touch the terminals or other charged parts of the switch while power is being supplied.
Doing so may result in electric shock.
(2) Be careful of electrostatic breakdown when handling.
(3) Do not drop or otherwise apply strong force to the switch.
(4) Do not place heavy objects on the switch.
(5) Do not operate or use the housing (switch unit) by itself. Use the switch with assembled the illuminated part (LED module or button).
(6) Pushbutton switches are designed to be operated by fingertips. Operating the switch using a sharp object (screwdrivers, tweezers, etc.), hard object(metal, etc.), or with a large or sudden force, may cause deform or damage the switch.
(7) Do not use the switch under loads that exceed the rated switching capacity or other contact ratings. Doing so may result in welding of the contact,or burnout accidents.

Sunmulon Co., Ltd.

PRECAUTION-1

Safety Precautions for All Illuminted Pushbutton Switches(8) For inductive load, the arc by back EMF may cause contact failure. Insertion of arc prevention circuit as the following is recommended.
Circuit

Element selection

Diode

L

C

R

Circuit

Element selection

The diode must withstand a peakinverse voltage 4 times higher thanthe power supply voltage and regarding
a forward current must as high or higher
than the load current.

L

C：1 to 0.5 μF × switch current (A)R：0.5 to 1 Ω × switch voltage (V)DCDC

The values may change according to
the characteristics of the load.
Determine ideal capacitance andresistance values through testing.
R

ZNR
Varistor

L

C
AC, DCL

Use a varistor that can withstandthe power supply voltage sufficiently.
(1.5 times or more)

AC, DC(9) Following circuits show examples of an anti-chattering circuit.
VDD

VDD

R

R1

VOUT
SW

R2
VOUT

C

SW

R
VDD

(10) Illumination(a) Do not apply a voltage between the LED terminal that is greater than the rated voltage. Doing so may damage the LED, cause lighting failure.
(b) LEDs cannot be lit directly by AC circuit should be provided rectifier smoothing circuit for products other than AC input type.

Correct

Incorrect
R
DC

AC

R
LED

LED

AC

(c) When wiring, pay attention to the polarity of the terminals.
(d) Simultaneous lighting may not be possible with Dual-Color illumination or Split-Face illumination (2, 3, or 4 split illumination), check the catalog.
(e) Apply voltage directly to LEDs of Non-built-in resistor type will damage the LEDs, so connect an appropriate external resistor.

(11) Wiring(a) Do not apply a soldering iron to the switch housing. Doing so may deform the terminals and cause defects.
(b) See catalog for models compatible with flux prevention measures terminal. Be careful not to allow flux to panetrate sliding parts such as buttons.
Use non-corrosive rosin solution as flux for dip soldering.
(c) For soldering other than flux-preventive models, hand solder with the terminals facing down to prevent flux from penetrating into the switch.

Correct

Incorrect(d) The housing of KA, K2, and K9 series are designed for reflow soldering.
(e) Use the appropriate wire size for the applied voltage and current, and solder properly. Use of the product with incomplete soldering may cause
abnormal heat generation, resulting in a fire hazard.
(f) After wiring is completed, maintain an appropriate insulation distance.

Sunmulon Co., Ltd.

PRECAUTION-2

Safety Precautions for All Illuminted Pushbutton Switches(12) Usage environment(a) Do not use in the presence of flammable or explosive gases such as gasoline, thinner, LPG, etc.
(b) Avoid using the product in places where corrosive or silicon gas is generated, high temperature, high humidity, sea breeze or direct sunlight.
(c) Provide appropriate protection when using the product in places where it is exposed to water, oil, metal powder, or dust.
(d) Do not use the product in a place subject to vibration or shock. It may cause malfunction or damage.
(e) When installed in a close grouping or continuously lit, the ambient temperature may exceed the specified value due to heat generation.
Take measures such as ventilation and lowering the operating voltage.
(f) When checking the actual equipment, load conditions and operating environment should be the same as the actual operating conditions.
(g) The ambient temperature for storage is －25℃ to 65 ℃ (No freeze, no condensation).

(13) When wiping off dirt on the exterior of the switch and accessories such as side plates, wipe lightly with a soft, dry cloth. Organic solvents such as
thinner, benzene, alcohol, or other acidic chemicals may cause deformation, discoloration, or malfunction.
(14) Store the product away from malignant gases, dust, high temperature and high humidity, and keep it in our packing condition.
(15) When removing the illuminated part (or button) from the alternate switch housing, switch state should be in a free state.

Correct

Incorrect

Removal in a locked state may cause malfunction or damage
to alternate switch.

Illuminated part
(Button)Free state

Locked state(16) Periodic inspection and replacement(a) Although mechanical and electrical durability are listed in the specifications column, deterioration of various parts (deterioration of resins andcorrosion of metal parts) is possible due to the operating environment and method of use. We ask that you implement inspections for Sunmulon
products to prevent accidents from occurring by conducting periodic inspections and replacements.
(b) When the switch is left unused or stored for long periods, contact reliability may deteriorate due to oxidation of contacts, which may cause continuity
failure, etc. Therefore, it is necessary to check the operation before use.

(17) Service scope
The price of Sunmulon products do not include the cost of services, such as dispatching technicians.

Sunmulon Co., Ltd.

PRECAUTION-3