Feature:1. 38 Ringtones and 4 Speed Volume: The wireless doorbell features 38 music options, with music switch, 4 speed volume adjustment, including mute flash to meet different needs.2. Multiple Functions: The self powered doorbell can display time, temperature, and humidity, with Fahrenheit and Celsius setting for real time temperature control. Can be switched between Celsius and Fahrenheit to meet different countries' needs.3. HD Digital Display: The classroom house wireless doorbell features high definition digital display with ambiance design, based on high brightness PC board screen to greatly enhance visual enjoyment.4. Easy to Install: The plug in wireless doorbell is plug and play, simply insert the doorbell receiver into a socket. Fix the button on the wall with double sided adhesive tape.5. Long Distance Transmission: This high frequency electronic wireless remote doorbell uses FM signal technology, interference resistant, with a range of up to 100m.Specification:Item Type: Wireless DoorbellMaterial: ABSInput Voltage of Receiver: 85-260V ACTransmitter Power Supply: Self powered (converts kinetic energy into electrical energy by pressing the button; no battery, generates automatic power)Waterproof Rating: IP44Operating Temperature: 0C-99COperating Frequency: 433.92MHZRingtones: 38Volume: 4 Speed AdjustableTemperature Display: Celsius Fahrenheit AdjustableTime Display: 00:00.Package List:1 x Transmitter2 x Receivers1 x Instruction Manual