This is a dual channel transmitters that are activated only after having entered a Suitable combination.The units are designed compatible with 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 DC2PCS CR2032 Li batteryBattery life:2 years(4 times operation every day)Frequency:433.92MHz+/-75KHzTransmitter power:1MwData compatible withmat:standardWork temp:-20~+55 centidegreePassword number:0-8Water proof level:IP54Material:Plastic + Metalcolour:Black + grayPackage Contents:1 x Keypad1 x English ManualOnly 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.