A. Stronger anti-error report and much better detecting ability. C. Easy to install, absolutely wireless, power supply built-in, wireless telegraph transmitting signal. D. Save power design&high capacity, it lasts longer than other wireless infrared detector. E. Extending socket built-in, compatible with wireless multi-host. Power supply: 1.5V high alkaline battery. 2500mAH Working current: static < 30uA; alarm < 20 Ma Self-check: 1~2 minutes