Description:1.Actuation Distance:10-15mm.Silver gray zinc alloy housing.2.The reed switch is an electrical switch operated by an applied magnetic field.3.Designed for use with alarm systems. Great for use in family and factory window, door. etc.4.Screw Mounted for easily install.5.NO means Normally Open: when the magnet separate, the circuit is conductive( light on );When the magnet together, the circuit is not conductive ( light off ).When make order,pls check carefully! 6.NC means Normally Closed: when the magnet separate, the circuit is not conductive( light off );When the magnet together, the circuit is conductive ( light on ).When make order,pls check carefully! Specification:Product Name: Magnetic Door SwitchModel: MC-51Contact Type: NOActuation Distance: 10-15mmMax. Current: 0.5AMax. Power: 10WWorking Voltage: DC100VSize(Approx): 31.5 x 15 x 7.6mm / 1.24 x 0.59 x 0.3 inch (L*W*H) Hole Dia.: 3.2mmCable Length(Each): 25cm / 9.8-inchMaterial: Zinc Alloy (Housing)Wire Type: 1007UL#22AWGColor: Silver GrayNet Weight: 43g Package Content:1 x Magnetic Door Switch