This is a two-channel transmitter that activates only after entering the correct combination. 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 200m in open space and 35m indoors. The units are designed for a battery life of approximately 2 years of operation - considering 10 transmissions/day. Power: 6 Volt DC 2 CR2032 Li-battery Battery life: 2 years (4 times use each day) Frequency: 433.92MHz +/- 75KHz Transmitter power: 1Mw Data format: standard Operating temperature: -20~+55 degrees Celsius Password number: 0-8 Waterproof rating: IP54 Material: Plastic + Metal Color: Black + gray Package contents: 1 x Keypad 1 x English manual