The units are designed 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 200m in open space and 35m indoors This is a dual channel transmitters that are activated only after having entered a Suitable combination The units are designed to battery life equivalent to an estimated 2 years of oper- considering 10 transmissions/day, Weight: 0.51588169308 pounds, Manufacturer: Jaywool