Liger Portable Waterproof Wireless Doorbell KitWireless doorbell kit, install battery operated transmitter outside using adhesive mounting tape or screws, receiver chime unit plugs into the wall; maximum effective range 325 ft. Use as a residential or business doorbell, or home paging device. Select from 38 tunes, from the standard sound to any several well known and fun melodies, volume adjusts to 4 settings Blue LED flashes when someone is at the door. Super efficient eco power management