This is a two-channel transmitter that is only activated after a suitable combination has been entered. The units are designed for indoor or outdoor installation, ensuring maximum security as the transmitted code changes with each transmission. The estimated transmission range is 200 m in open space and 35 m indoors. The units are designed for a battery life equivalent to approximately 2 years of operation - based on 10 transmissions/day. Power: 6 Volt DC 2 pcs CR2032 Li-battery Battery life: 2 years (4 times use every day) Frequency: 433.92 MHz +/- 75 KHz Transmit power: 1 Mw Data format: standard Working temperature: -20~+55 Celsius Password number: 0-8 Waterproof level: IP54 Material: Plastic + Metal Color: Black + grey Package contents: 1 x Keypad 1 x English manual 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 +/- 1-3 cm.