Waterproof Wireless Doorbell, Play and Plug Doorbell No Batteries, Chime with 38 Melodies 3 Adjustable Volume and Blink LED Doorbell Kit Easy Install for Home Classroom, Operated at 488 ft/150 m

UNIQUE BATTERY-FREE DESIGN: Through the finger press to generate electricity, kinetic energy into electrical energy to transmit wireless signals, eliminating the need to replace batteries.
38 CLEAR SOUNDS TO SELECT: Rich and clear sound, 3 adjustable volume levels, Different 38melodies to meet various needs.
IP44 WATERPROOF: IP44 dust and water protection level, operates in temperatures between -20 °C to 60 °C ensure it can withstand the harshest weather conditions.
488 Ft/105 M RADIO WIRELESS COVERAGE: The strong and stable wireless signal anti-interference with other devices in your or your neighbours' home, ensure that you're never to miss a visitor, even if you're a few rooms away or on another floor.
EASY TO INSTALL & EXPANDABLE: Free power glue, you can use the power glue to install, or use the screws to installto a wall without wiring; You could install it anywhere inside, for home, garden, office, store, mailbox etc.