This is a dual channel transmitters that are activated only after having entered a Suitable combination 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 The units are designed to battery life equivalent to an estimated 2 years of oper- considering 10 transmissions/day Power:6Volt DC Frequency:433.92MHz+/-75KHz Transmitter power:1Mw Data format:standard Work temp:-20-+55 centidegree Password number:0-8 (The product appearance and printed words depending on the batch, but this does not affect use) Color: As Shown Material: plastic Package Contents: 1 x Receiver 1 x Wireless Keyboard Transmitter Only 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 measurement allowed error is +/- 1-3cm.