This is a dual channel transmitters that are activated only after having entered a Suitable combination. The units are designed suitable for installation in indoor or outdoor locations that ensures the utmost security because the transmitted code is changed at each transmission session. The estimated transmission range is 200 m in open space and 35m indoors . The units are designed to battery life equivalent to an estimated 2 years of oper- considering 10 transmissions/day. Power:6Volt DC 2PCS CR2032 Li battery Battery life:2 years(4 times operation every day) Frequency:433.92MHz+/-75KHz Transmitter power:1Mw Data suitable format:standard Work temp:-20~+55 centidegree Password number:0-8 Water proof level:IP54 Material:Plastic + Metal colour:Black + gray Package Contents: 1 x Keypad 1 x English Manual Only the above package content, other products are not included. Note: Light 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.