Features: 1.Using high?quality ABS shell material, fire?retardant, sturdy and durable, long service life. 2.This doorbell is designed with a built?in speaker. Once someone presses it, it will emit a loud ringtone, and you can hear it at home, and you don't have to worry about missing visitors. 3.It adopts wired design, no need to buy any battery, just use the access control power supply, which is environmentally friendly, convenient and cost?saving. 4.This wired doorbell is very convenient to operate and install. Wall hanging or double?sided adhesive paste installation(not include double?sided adhesive). 5.Suitable for family, hotel, building. It is an external wired doorbell used for secure access control. Specification: Item Type: Wired Doorbell Material: ABS Application: Suitable for family, hotel, building Working Power Supply: Voltage: 12V DC Operating Current: 20mA Ambient Temperature: Working: -10 - 45 Relative Humidity: Working: 40%RH - 90%RH PackageList: 1 x WiredDoorbell