Feature: 1. Simple Installation: The installation of the doorbell requires no tools or electrical expertise, easy and convenient while contributing a stylish accent to the face of any home. 2. Sound Library: The wireless doorbell does not commit to one single sound every time the door rings, not bound to any one sound, containing a library of 38 music chord, good resonance effect and not harsh. 3. Not Only Doorbell: The doorbell has a strong and unique sound, can be hung on the old man's chest as a pager, convenient for find the problem and avoiding safety risks care more timely. 4. Frontal Cavity Design: The doorbell has front horn, sound transmission without obstruction, sound crisp without noise, transmission longer distance up to 30 meters. 5. Small And Portable: The doorbell has small size and light weight, portable, can be taken to anywhere for convenience at home or indoors. Specification: Item Type: Wireless DoorbellMaterial: ABSOperating Temperature: -20℃ to 60℃Battery: CR2032 Battery type: Button CellBattery Model: cr2032Battery capacity: 100mAh Waterproof Level: IP44 waterproofStandby Power Consumption: 0.25WOperating Frequency: 433.92MHZ.Music: 38 Songs Volume: 4 Gears (Including Mute)Controllable Volume: 0-90dB Receiving Distance ≥ 200m Receiver operating Temperature: -10℃ to 45℃ Package List: 1 x Transmitter 1 x Receiver 1 x Instruction1 x Double Sided tape