<b>Why choose SECRUI Plug-in Wireless Door Bell ? </b><br> <b> 1. Expandable with Additional Receivers/Transmitters</b><br> Thanks to its simple code pairing way, you can expand your existing SECRUI wireless doorbell system with up to 2 transmitters and multiple receivers for your family or office needs. <br><br> <b>2. Ultra-long Transmission Distance</b><br> The wireless transmission range between the doorbell chime receiver and the doorbell push button is up to 300M. <br>With the ultra-long wireless range, this cordless doorbell can be used not only in apartments but also in villas and big houses. It can also be applied in business, office, store, classroom, etc. <br><br> <b>3. Colorful LED Flash Light Indicator</b><br> Not only the transmitter blue indicator will light up when press the button, but also the colorful LED indicator on the chime receiver flashes. <br>This feature is also helpful for those with a severe hearing impairment. A perfect wireless doorbell for elderly. <br><br> <b>4. Five Adjustable Volume Levels & 32 Chimes</b><br> From silent to loud, a great option for different environment. You can set the doorbell to silent mode or lowest volume mode at night. It means you can still hear the bell and the kids don't wake up! Classic and seasonal melodies, a selection of standard 'ding dong' sounds. You could pick a different jingle for everyday.<br><br> <b>5. Easy Installation</b><br> The plug-in main bell units and a bell push with a strong double sided adhesive pad, just had to stick the door bell on the door and plug in the receivers in the socket. If you want to secure the doorbell in a more permanent fashion, it also comes with 2 screws.<br><br> <b>Parameter: </b><br> Different transmitters can be set to different tunes<br> Memory function to retain settings when receiver is unplugged or off<br> Power: 100~240V<br> Transmitter button battery: 3V CR2032<br> Standby current: ＜3mA <br> Working current: ＜11mA<br>