Whether it’s a residential or commercial installation, the BMD503 Digital Quad PIR and Microwave Detector (Dual Technology) with Anti-Masking and Pet Immunity readies a wired security system for the unexpected by providing protection for every room, corner and corridor. The BMD503 effectively blends performance with competitive pricing. The detector features intelligent signal analysis for reliable detection, pet immunity up to 25 kg (55 lbs) and a slim design that complements any décor. The microwave sensor of the detector features two channels, one for microwave (MW) detection, and the other for anti-masking detection. The anti-masking feature works by sensing intruders who approach the detector from the distance of 0.8 m and closer. If the field of view of the detector is intentionally obscured by an intruder, the anti-masking relay opens (switches from NC to NO) and remains in this status until the PIR sensor is activated.