Features: 1. Adopted premium abs shell material, fireproof and antiflaming, sturdy and durable, long life service. 2. 90dB build-in loudspeaker, produce clear and loud ding dong playing bell sound, not afraid of can't hear doorbell. 3. No need to replace or add battery, using access control power supply, which is eco-friendly, convenient and save money. 4. Easy to install, wall-mounted or double-sided adhesive paste. 5. External wired door bell for security access control. Specification: Condition:100% Brand New Material: ABS plastic Color: As Pictures Shown Voltage: 12V DC Operating Current: 20mA Working Temperature: -10-45 Relative Humidity: Working: 40%RH-90%RH Installation: Wall-mounted or double-sided adhesive Red: VDC + 12 V Black: GND Green: BELL1 Yellow: BELL2 Size: approx.86*86*25mm/3.4*3.4*1in Weight: Approx.81g/2.9oz Package list: 1 * Doorbell Note: 1. Please allow 0~1 inch error due to manual measurement. Thanks for your understanding. 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.