No battery needed, press with your finger to generate electricity, the transmitter has a built-in kinetic generation module and press the doorbell to convert the mechanical energy into electrical energy to generate a wireless signalRainproof and dustproof function, improved design of vertical structure rainproof, wind and rain do not affect the useOne thing with two purposes is not only a doorbell, but can also be used as a pager, a pager for the elderly, a pager for pregnant women and a baby pager to protect your family when you sleep soundly at nightLong-distance transmission has strong penetrating power, 150 meters long-distance transmission in an open area and 30 m long-distance transmission in a room.Innovative research and development of energy harvesting generators, after 200,000 continuous press tests to a long product lifeReceiver size: 78x54x20mmTransmitter size: 66x40x20mmcolor: As shownMaterial:ABSPlug Type:EU plug, it applies to Indonesia, Germany, , , Italy and so onVoltage: AC220VPackage contents:2 x Transmitter1 x ReceiverOnly 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 allowed measurement error is +/- 1-3 cm.