Wireless Doorbell, Hallomall Wireless Long Range Door Chime with 900 feet 52Chimes, Waterproof Transmitter, 4-Level Volume (B7) Super Long Working Distance: The wireless doorbell kits support 900feet operation range in open space. IP55 Waterproof Transmitter. The transparent compartment at the bottom of the transmitter allows visitors to leave message for you. Easy Installation without wiring. Plug receiver into an electrical outlet. Mount transmitter through double-sided adhesive tape or included screws / anchors. Ideal for calling the elderly, children, nanny or patients. If you have an elderly care patient that needs to be able to ring/alert a single main chime unit from two rooms. 52 different ring tones. Four levels of adjustable volume from 25db to 110db