Wireless Doorbell Waterproof Memory Function Door Bell No Battery Eu Plug Smart Home Night Light Description: 1. 4 Modes: Sound only, flash only, sound &amp; flash, sound &amp; light on.Light on mode can turn into a night light 2. Memory function: After the power is turned off, remember the music set before. No need to set music again 3. Self-powered doorbell that requires no battery,Don't worry if the battery has power, so Don't miss important visitors 4.Gorgeous lights, loud ringtones. Especially suitable for the elderly, pregnant women. 5.Self powered button.This button uses kinetic energy. No battery required Specifications: 1. Receiving distance: 150 M (in open area) 2. Volume: 4 files 0-100DB, ringtones: 58 pcs 3. Rated voltage: AC 110~ 240V ,50-60Hz 4. Working frequency: 433MHz. 5. Receiver standby power:< 0.5W 6. Receiver size: 86X78mm 7. Button size: 80x41mm Package Included: you can choose: 1*receiver, 1*transmitter 2*receiver, 1*transmitter 1*receiver, 2*transmitter 2*receiver, 2*transmitter