Passive infrared managed by microprocessor with supervised wireless transmission of alarm signal powered at 3 VDC. Uses a pyroelectric sensor of the latest generation with filter for white light and RF interference. Automatic control of sensitivity to changes in ambient temperature. Manual adjustment of sensitivity via trimmer. A special analysis of the detected signal allows further control of the form and polarity of the signal, thus distinguishing a real alarm signal from a simple interference signal. Operation blocked for 2 minutes after each alarm to reduce battery consumption. New Fresnel lens with 25 zones on a 4 planes at 90°. It is possible to request lenses for tent coverage, long range coverage and for homes with pets. Radio range: 300 m in open field, external directional antenna can be connected. SNI swivel joint available on request (see accessories) The same unit exist also as WIRED under Ref : BS 12 with Micro wave