Wireless Doorbell, AVANTEK Waterproof Chime Kit, Operating at 300 Meters, 2 Plug-in Receivers, 36 Melodies to Choose From, 4 Volume Levels, Black (DB-12W1) PORTABLE DOORBELL: Includes 1 transmitter, 1 plug-in receiver and 1 battery-operated receiver; the battery-operated one is so portable that you can take it anywhere in your house or yard SUPER LONG WORKING DISTANCE: Supports up to a 300 m / 1000 ft operating range; makes sure that you never miss a visitor or delivery again, whether you are occupied in the kitchen or the garden STRONG ANTI-INTERFERENCE: One code for one kit system ensures no interference with other equipment or from neighbors; no more annoyance of responding to other peoples doorbells WATER-RESISTANT TRANSMITTER: Withstands most weather conditions with an ingress protection grade of IP44; consumes very little energy and gives you years of dependable performance BROAD USAGE: 36 various ringtones with 4 adjustable volume levels; ideal for homes, office buildings, hotels, factories etc.; it can also serve as a paging device, which is especially useful as an in-home emergency alert for the elderly