1This is a set of magnetic detecting switch used to protect doors and windows for the most part. 2Protective device monitors the opening and closure of doors and windows 3High quality magnetic sensor contacts with strong magnetic, sensitive respond and long durability 4The wired part often be installed on the fixed door frame and the mating part is mounted at the corresponding place on the door 5Easy to install and use. A good replacement for the old contacts. Simple to install no hassles This set of magnetic sensor detector includes the wired part and the mating part, which is great for installed on doors of house,garage, warehouse, enterprise and shop etc. Keep your home safe with this set of door security accessories. Features: This is a set of magnetic detecting switch used to protect doors and windows for the most part. Protective device monitors the opening and closure of doors and windows. High quality magnetic sensor contacts with strong magnetic, sensitive respond and long durability. The wired part often be installed on the fixed door frame and the mating part is mounted at the corresponding place on the door. Easy to install and use. A good replacement for the old contacts. Simple to install no hassles. Specifications: Condition: 100% New Material:Aluminum alloy Color: As Picture ShownSize(L x W x H): Approx. 106 x 38 x 10mm/4.2 x 1.5 x 0.4in Rated Voltage: 12V Rated Current: 120mA Sensing Distance: Within50mm / 1.9in Package Included: 1 x Set of Magnetic Detecting Contacts Note: Can not used alone. Should work with the alarm system main unit for alarming.