Smart learning mode User-friendly design Strong Signal - It can penetrate 3-4 walls and wireless range up to 150 meters in open area,great for large house including villas, apartment,offices,shops,warehouses.etc. IP68 Waterproof level - Rainy days can also be used,saed and durable 38 Songs Home Welcome Door Chimes - The doorbell can be muted when sleeping Not only a doorbell but also a pager - When the elderly,babies,and pregnant women sleeping alone have needs,press the transmitter and the bell will ring. Note 1. This product is a set, the receiver and controller purchased separately cannot be used, and need to be paired for use. 2. The button cannot be placed on the iron door, which will shield the signal. We recommend that the button be placed next to the iron door. Power consumption:0.25w Wireless frequency:433 MHz Operating temperature:Greater than -10°-+45°C Ringtone volume:Greater than 50dB/1m Transmitter:no need battery Wireless distance:150 meter(open space) Plug Type:EU Plug,it applies to Indonesia, Germany, France, Spain, Italy and so on. Voltage:AC100-240V Colour:White Material:plastic Size:Receiver size:L95xW54xH68mm, Transmitter size:L80xW50xH28mm Package Contents: 1 * Button 1 * Receiver Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.