- Easy installation: the wireless switch fits into the light fixture without wiring and is ideal for retrofitting staircase lights, hallway lights, or bedroom/hall lighting. Mounting screws and 3M tape are included. - Battery-free operation: pressing the switch activates and transmits the signal, with no battery required. Energy-saving and environmentally friendly. Service life up to 50 years or 200,000 keystrokes. - 433 MHz radio with long range: operating frequency is 433 MHz; up to 200 m outdoors and 50 m indoors. Can penetrate up to 3 walls. Do not install in a metal box, otherwise the signal may not be received. - Waterproof and safe: can be installed directly in the bathroom and is safe to use with wet hands to turn lamps and heaters on or off by radio. No risk of electric shock, and no special moisture or rust protection required. - Use scenarios: retrofit stairs for safer nighttime lighting; upgrade hallway or bedroom lighting without rewiring; convenient control of bathroom lights or heaters from within wet areas.