Easy to install. Keypad operated. Open field range of up to 125m. Fully expandable system - up to 12 PIRs. Solar powered siren uses daylight to maintain charge. 868MHz. Pack includes: 1 x wire free keypad. 2 x door/window contacts. 2 x PIR movement detectors. 1 x solar siren. Batteries, fixings and installation DVD. Requires 3 x 9V PP3 batteries (included) and 4 x CR2032 lithium coin cell batteries (included).