External wired doorbell, ideal choice for access control system Premium ABS plastic material, eco-friendly, waterproof, flame retardant. Anti-oxidation, anti-fading for maximum durability. 12V Doorbell Red: +12V, Black: GND, Green: BELL1, Yellow: BELL2. With high -90dB speaker. Featuring clear, loud and soft "ding dong" ringing sound. Ringtones: 3 chords to choose from. With Dingdong ring. Suitable for access control system, such as home, hotel, office, apartment, factory, etc. Features: 1) ABS material. Small and beautiful, can be used for a long time 2) External wired door bell for security access control. 3) Featuring soft, loud ding dong and clear playing bell sound. 4) Work with DC12V power supply. Don't need battery. 5)Easy and convenient to install, wall mounted. 6)With 90dB speaker.A good replacement for the old and broken Specifications: Material: ABS plastic Color: white Voltage: DC 12V Ringtone: ding dong sound Operating current: 20mA Installation: Wall mounted Decibel: 90db Size: 86*67*24mm Wiring diagram: Red: +12V Black: GND Green: BELL1 Yellow: BELL2