Home self-generated wireless doorbell Outdoor battery-free and wiring-free waterproof doorbell Easy to install without drilling Remote control distance 150M 60 bells Ambulance bell Nursing bell Elderly pager Wireless AC doorbell Plug-in wireless music doorbell. Self-generating waterproof doorbell. Power supply mode: transmitter self-generated, receiver plugged in Combination mode: One to one (1 transmitter + 1 receiver), one receiver can store up to five transmitter signals This doorbell does not require batteries, no wiring, plug and play, convenient and practical, easy to install Built-in 60 welcome music/4 adjustable volume levels (including mute) IP44 waterproof grade, can effectively prevent rain intrusion, sunproof and waterproof 150m remote control distance (open space) (this data is the barrier-free test distance of the open space in the experiment, the actual distance vary depending on the use environment and obstacles, please refer to the actual distance) The receiver is