No battery is needed to generate electricity and transmit signals by pressing the transmitter, which saves money and eliminates the hassle of changing batteries. Waterproof rating IPX4 can be daily waterproof (not immersed in water). If installed in a completely exposed outdoor environment, please use a waterproof cover. The remote control distance is 150M (in an open environment), and it is normally installed in an indoor environment of 20-30M (depending on the thickness of the wall). 38 Polyphonic ringtones can be selected with 4 levels of volume adjustment (high, medium, and low silent). Comes with adhesive and is easy to install. The transmitter can be fixed and installed with screws (accessories do not include screws). Characteristic Voltage AC110~240V 50/60Hz. Working environment: -10~45. 150M remote receiving distance (in open environment). 4 types of volume adjustment, silent can be set. Without batteries, mechanical energy generates electricity. Plug Type: EU Plug, it applies to Indonesia, Germany, France, Spain, Italy and so on. Color: picture color Material: ABS Package Contents: 1 * Receiver 1 * Transmitter Only the above package content, other products are not included. Note: Light shooting 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.