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 NewMaterial: ABS plasticColor: As Pictures ShownVoltage: 12V DCOperating Current: 20mAWorking Temperature: -10℃-45℃Relative Humidity: Working: 40%RH-90%RHInstallation: Wall-mounted or double-sided adhesiveRed: VDC + 12 VBlack: GNDGreen: BELL1Yellow: BELL2Size: approx.86*86*25mm/3.4*3.4*1inWeight: Approx.81g/2.9oz Package list: 1 * DoorbellNote: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..