HMW28/PRO is Microwave standalone motion sensor integrated with Hytronik True presence detection technology, On/Off control with one relay channel output, which is NO (normally open contact). The Hytronik True presence detection technology works to detect human breathing rather than the mirror movements. No matter if the person sit/stand statically or turns their back to the sensor. The sensor can accurately recognize presence and keeps the lights on all the time. It is ideal for typical indoor applications such as classroom, of­ce, healthcare, and other commercial areas.