ST102 sensor.FEATURES : Double detectors, SMD technology; three indicators; pulse width adjustable; preventing false alarm function; preventing pet design; shape is delicate and cabinet , installation is convient and flexible.Note: You should choose the installation position where the signal motion orientation can vertical with the sense direction. In front of detecting window there should be no block or moving object to affect detection; Avoid installing the unit in the zones direct sunlight or air stream and temperature alter obviously for example: air condition, air heating.