High quality presence detector from Niko (previously known as Servodan). The 41-300 is an excellent sensor for large areas, like open plan offices, car parks hallways, change rooms and etc.
The sensor uses a triple element PIR detector to achieve excellent coverage, is surface mounted and is a favourite in under cover car parks due to its easy installation, large coverage area and affordable price point.
The coverage area can be increased by wiring multiple units in parallel.