This dual-channel transmitter activates only after entering a valid combination. Designed for indoor or outdoor installation, ensuring maximum security with a rolling code that changes with each transmission. Estimated transmission range is 200m in open spaces and 35m indoors. Units are designed for an estimated battery life of 2 years, assuming 10 transmissions per day. Power: 6 Volt DC 2 x CR2032 Li Battery Battery Life: 2 years (4 transmissions per day) Frequency: 433.92MHz+/-75KHz Transmitter Power: 1mW Data Format: Standard Operating Temperature: -20~+55 Celsius Password Number: 0-8 Waterproof Level: IP54 Material: Plastic + Metal Color: Black + Gray Package Contents: 1 x Keypad 1 x English Manual (Other products in the image are not included). Note: Light and different displays may cause the color of the item in the picture to be slightly different from the real thing. The allowed measurement error is +/- 1-3 cm.