A wireless doorbell loud enough for anywhere - adjustable volume and silent mode. 0 to 120 dB, 32 selectable melodies. Memory function allows the plug-in doorbell to remember the last ringing tone and volume, even after a power failure, without the need to reset. Long range plug-in doorbell - extra long wireless range up to 300 metres. The powerful and stable wireless signal ensures that you never miss any visitors, even if you are in a large house with several rooms. Whether it's upstairs or in the basement. IP55 Waterproof - Ultra-low power consumption and CR2032 lithium batteries give it a lifespan of up to 3 years; no need to worry about frequent battery changes; IP55 waterproof rating to withstand the harshest weather (-4 °F to 140 °F). LED indicators - The 7-colour LED indicators on the plug-in receiver flash when the transmitter is pressed and a signal is received. They alert those with impaired hearing or when the sound of the doorbell is (temporarily) undesirable. If no ringing is required, the cordless waterproof doorbell can be muted to provide visual notification via LEDs when someone appears at the door. Cordless doorbell receiver and buttons are expandable - factory paired and different transmitters can be set to different tunes. Expandable up to 20 doorbell kits. With multiple cordless doorbells, you can configure a different ringtone for each door. Know exactly which door your visitors are calling from. This is handy for homes or offices with multiple entrances. Search "SECRUI" on Amazon to find doorbell accessories.