Case 7:20-cv-02945-MCR-HTC Document 20-8 Filed 08/09/22 Page 1 of 7
How Fo,ding the Flanges Back Affects REAT Results 

of the UltraFit Earplug End of the Combat Arms Plug 

E-A-R 00-12/HP 

R. W. Kieper, B.S. 

E. H. Berger, M.S. 

AEARO Company 

E•A•RCAL sM Laboratory 

7911 Zionsville Road 

Indianapolis, IN 46268-1657 

phone: 317-692-1111 

fax: 317-692-3116 

July 10, 2000 

Version 1.2 

E•~RCAL511 Laboratory is accredited by the National Institute of Standards and 

Technology, National Voluntary Laboratory Accreditation 

[~J~a£. ri\i Program, for the measurement of attenuation of hearing 

~ protection devices re ANSI S3.19-1974 and ANSI 512.6-1997. 

Laboratory Code 100374-0. 

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P-GEN-00001.1 Case 7:20-cv-02945-MCR-HTC Document 20-8 Filed 08/09/22 Page 2 of 7
INTRODUCTION. 

The Combat Anns earplug was shortened, at the request of the Army, so that it would fit into a carrying : 

case. Because of this; the plug is shorter than any other UltraFrt Plug design. The purpose of this report; 

is to document that the current length of the UltraFrt Earplug end of the Combat Anns Plug is loo short , 

for proper Insertion, and how changing the fitting technique affected the results of reaf·ear tests of thls 

plug .. 

DEVICE TESTED ' 

The Combat Arms Plug consists of two UltraFrt®-type earplug tips joined together with a hard, plastic» 

stem (part no. 4046-1, see Figure 1). The two plugs were tesled independently because they afford .-

different levels of noise reduction; The level-dependent plug (part no. 2039·0} is yellow and has a 

channel through the plug, into which a filter has been placed;. The solid plug end (part no. 2068-0) ls · 

green and it was this plug which was evaluated in two separate REAT tests - 213015 and 213017~ This 

plug is the linear·earplug end of the Combat Arms Plug . 

TEST PROCEDURE 

Both tests followed the S3.19·1974, Experimenter-Fit protocol, so the plugs were tested three times each 

on subjects from the E·A:RcAL Laboratory lest panel. After each fitting by the experimenter, prior to the ·· 

experimenter leaving the test chamber, a fitting noise was presented and the subject was allowed to 

adjust the plugs for maximum noise reduction, if s/he deemed it necessary. 

For test 213015, the plugs were fit according to the standard plug's fitting Instructions, with no 

modifications. Because the stem of the green, solid end of the plug is so short; it ""3S difficult for the 

experimenter to Insert the plug deeply into some subjects'. earcanals, especially those subjects with 

medium and larger earcanals. Additionally, the geometry of the earcanal opening sometimes prevented . 

the deep plug insertion required for maximum attenuation values. When the solid plug was fitted during ·• 

the first test (·015), the basal edge of the third flange of the yenow, level-dependent plug sometimes 

pressed against the subject's earcanal opening and folded up . . When the inward pressure on the plug . 

was released, the yellow plug's flanges tended to return to their original shape and this sometimes 

loosened the plug, often imperceptibly to the subject. 

For test 213017, the yellow flanges of the level-dependent end of the plug were folded back prior lo the · 

green; solid plug being inserted into the subjects' ears:. The folded-back flanges and the hard plastic · 

stem provided a long, stiff quasi-stem for the experimenter to grasp and allowed for a deeper and 

more-consistent fit of the solid plugs for test 213017: When folded back fn that way, the yellow flanges 

neither touched the subjects' conchae nor compromised the fit of the solid earplugs. 

':, . ;. 

RESULTS 

Tables 1 and 2 are the Individual Subject Data from tests 213015 and 213017; Figure 2 is a graph 

comparing the means and standard deviations obtained in these two tests._ The initial test 213015was .· 

stopped after eight subjects because the Individual results were variable and the NRA was quite low (11 ). 

Ten subjects were tested in test 213017. The means from that test are from 0.6 to 4.5 dB higher at all 

test frequencies and the SOs are 0.6 to 4.9 dB lower than those of test 213015. The 2-a NRR obtained 

from this test is 22 dB. 

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P-GEN-00001.2 Case 7:20-cv-02945-MCR-HTC Document 20-8 Filed 08/09/22 Page 3 of 7
Table 1 - INDIVIDUAL SUBJECT DATA 

Test ID~ 213015 Device: Short-stemmed UltraFit Plug, part of Combat Arms Plug 

Date: 1/25/00 Samples: 10 Position: NA' Comfort:. 3.1 

Comments: Plugs are the green end of the Combat Arms Plug. 

1/3 Octave-Band Frequency' Canal 

Subi. Trial 125 250 500 1000 2000 3150 4000. 6300 8000 125 Comf. Size NRR* 

KJC 1 32 30 32 32 32 38 37 39 41 31 SIS+ 22.5 

2 28 30 32 24 26 39~ . 37 44 44 27 

. 3 34 31 35 32 31 42 44 50 45 30 3 

MKF 1 30 26· 31 25 32 40 36 44 49 31 Xs../XS· 242 

2 ·. 38 35 40 34 34 44 46 50 51 37 

3 35 34 37 31 32 41 44 51 49· 34 1 

GWG 1 17 23 26 22 31 38 39 49 49 19 MIM+ 16.9 . 

2 40 40' 41 39 36 38 46; 49 so. 37 

: 3 39 39 38 40 34 42 44 50 47 37 3 

BAK 1 27 22 19 20 25 35' 40- 46 45 29 XUXL 7.8 .. 2· 49 48 53 43 41 53 _49. 55 45 45 . 

3 41 37· 37 28 33: 46' ' 46. 51-. 47 37 2 

RTM 1 19 25 21 24 30, 32"' 31 37 35 19 LJM+ 20.1 

2 33 27. 29 28 34 . 38 .. 40 39 45 28 ; 3 23 21 22 26 32 33 33 33 38 26· 2 

TLS 1 44 43 40 34 37 39 . 39 48 39 40 M+!M 28.3 ·. 

2 33 36 35 28. 36 42· 42 45 39 35 

3 41 39 42 35 36 47 I 43 48 44 38 2 

TRS 1 7 2 -4 0 ~2 13 8 5 6 0 SIS -12.5 . 

2 28 21 25 26 23 18 14 34 36 26 

3 25 22 24 22 20 27 29 41 38 26 2 

JMW 1 31 31 32 31 31' 38 - . 38 46 42 30 M/M+ 9.1 

2- 17 18 14 16 24 24 22 28 26 13 

3 21 24 25 21 32 33 34 36 39 26 10 

' 

Mean 30.5. 29.3 30.3 27.5 30.6 36.7 36.7 42.4 41.2 29.2 3.1 14.5-

sd(24} 9.9 9.8 11.4 8.9 6.3 9.0 10.1 10.5 9.5 9.6 - - sd(B) 7.2 7.8 8.4 5.8 5.5 8.2. 9.2 8.4 7.5 2.9 13.1 · 

a-Value 26.8 18.3 10.6 9.8 16.9 16.6 22.9 I·. 

NRA (2sd) = 10.9 (1sd} = 20:3 (Osd) ~ ' 29.1 NRA•· Individual 2sd NRA 

"4 • • 

l -

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P-GEN-00001.3 Case 7:20-cv-02945-MCR-HTC Document 20-8 Filed 08/09/22 Page 4 of 7
" i 

Table 2-INDIVIDUALSUBJECT DATA 

Test 10: 213017 · Device: Short-stemmed UltraFit Plug, part of Combat Arms Plug· 

Date: 5/9/00 Samples: 10 Position: NA Comfort 3.1 

Comments: Plugs are the green end of the Combat Arms Plug: The yellow flanges were folded outward 

to allow a deeper insertion of the green plug.· GWG failed the Extreme Range Test; He was·· 

re t este d : Th e onqma • ' I NRA was 21 

Lt 1/3 Octave-Band Frequency Canal· 

Subi. Trial 125 250 500 1000 2000 3150 4000 6300· 8000· 125 Comf. Size NRR• 

KJc· / 1 32 35 36 34 32 44· 46' 45 44: 33: SIS+ 26.6 ; 

2 32 30 32. 27 30 41 44 46 45 28 

3 32 34 39 33 32 45: 48: 46 44 32 4 

GWG 1 41 41 40 36 37 39 46 48 46 35 MIM+ 32.1 

: 2 41 42 41 37 38: 41 47 49 48 37 .. 3 35 37 37 37 33 35· 42 50 49 31 2· 

JTH 1 30 30· 33 35 34 37 38: 50 52 35 XS/XS - 21.9; 

2 • 31 27 27 26 30 28 29 35 39 29 

I 3 35 29 30 28 32 35 41 49· 49 35 B 

BAKlf 1 . 36 35 35 27 39 32 34• 46 40 33 XUXL 24.6 

2 41 36 36 38 39 30 34 45 42 36 

3 40· 33· 33. 34 38 29 'Zl 49 45 33 2 

RTMJ 1 30 37 34 29 40 48 40 39 40 32 UM+ 17.8 ; 

2 24 25. 25 27 31' 36! ·, 33 32 31 21 

; 3 22· 20 25 27 29· 30 27 27 34· 24 3· : 

OLP )· 1 40 38 41 42 40 32. 33 51 50 42 L+IL+ 30.2 

2 ·. 35 36 39 39 36 . 38, . 39 56 54 38 

3 41 39 42 39 45 33 .; 39 46 53 42 2 

EAS 1 25 25 26 30 38 41 36 42 35 24 MIM+ 25.0. 

2 33 36 35 33 35· 37 39 40 44 34 

; 3 31 27 30 33 32 40 39 39 42 31 3 

TLS J. 1 35 32 36 38 33 44 46 45 40 39 M+IM 19.6 •. 

2 32 25 24 23 33 36 40 45 40 25 

3 34 35 34 33 34 41 40 48 43 34 2 

KKS 1 25 20. 21 22 30 35· . 37 35 34 26 M/M+ 20.0; 

2 23 23 19 22 30 30 31 35 31 23 

3 20 23 24 26 31 35 36 33 32 18 1 

DLW 1 36 36' 41 33 35 43 42 46 52 41 S/XS+ 26.0 ,. 

2 34 32 40 37 29 43 48 51 54 35 

3· 35 36 36 36 41 41 47 45 48· 37 4 

Mean 32.7 31.S 33.0 32.0. 34.5 37.3. 38.9 43.8 43.3 32.1 3.1· 24.4' : 

sd(30) 5.9 6.1 6.5 5.5 4:1. 5.3 1 6.1 6.7 6.9 6.2 - - sd(10) 5.6 5.3 6.0 4.7 3.2 4.3 5.3 6.1 6.5 2.0 4.6 

0-Value 36.9 28.1' 23.2 21.0 25.0. 25.7 31.0 ; 

. 

NRA· {2sd) = 21.7 {1sd) = 27.3 (Osd) = ' 32.8 NRR• - lncfwidual 2sd NRR • 

; ; 

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P-GEN-00001.4 Case 7:20-cv-02945-MCR-HTC Document 20-8 Filed 08/09/22 Page 5 of 7
- DET QlY PART NUMBER DESCRIPTION 

A 2039-0 

8 2068-0 

c 4046-1 

D 4047-A 

NONLINEAR EAR PLUG 

ULTRAFLEX EAR PLUG 

NONLINEAR ULTRAFIT STEM. BARBED &. REVERSIBLE 

FILTER FOR NONLINEAR PLUG. - 2 HALVES ASSEMBLED 

¢.073[1.85]--j 1 t-- --r-r--1~~~~~~----,-~~l 

¢.073[ 1.85] 

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¢.312(7.92]-'--~-----

.642[ 16.31 J 

.120(3.05] ' 

1.404(35.66] 

.642[16:31] 

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DIMENSIONS ARE NOMINAL AND IN INCHES AND (MILLIMETERS] 

SIGNATllR£S DATE 

DRAWN 8\'; M. DOTY 3-23-98 TITlE 

3 ~27-99 DET D WAS 4047-0 MLO RNt CHECl<EO BY: R. FALCO 3-24-98 

2 M7-99 DET B WAS 2032-B. 0AL WAS . T.588 MLO RNt PIWJECT ENGINEER: R. FALCO 3-2~-98 

I 1-11-99 nn.E CHANGED. NOMINAL NOTE AOO£D MLO RNF OPERATIONS; REr NO. 

IEN«J CCMPAN'I' 

7911 ZJONSVIU.E ROAD 

INOIANAPOUS. IN 46268 

COMBAT ARMS 

EAR PLUG ASSEMBLY 

I SCALE: 4X SHT. 1 OF 1 

2041-3 REV OOE DESCRIPTION BY M'f'N POSITIVELY- NO CHANGES MAY BE MADE TO IORA'NING NO. 

REVISIONS IAATERIM.S OR OJUENSIONS lt1THOUT WRITTEN APPROVAL 

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P-GEN-00001.5 Case 7:20-cv-02945-MCR-HTC Document 20-8 Filed 08/09/22 Page 6 of 7
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P-GEN-00001.6 Case 7:20-cv-02945-MCR-HTC Document 20-8 Filed 08/09/22 Page 7 of 7