SECM1033 Features: * Wireless transmitting distance up to 450 ft * 4 cm alarm distance * Used for Air-Alarm Ii * Host LED light flashes when door is open * Host chirps when door is open and closed Specifications: * 23a 12v alkaline battery lasts up to 2 years Dimensions: * Dimensions: 3" H x 2" W x 1.5" D