Description: Product Name: Magnetic Door Contact Reed Switch Feature: A reed switch is an electrical switch operated by an applied magnetic field. Switch Type: NO/NC, NC means Normally Closed:When the magnet together, the circuit is conductive( light on ); when the magnet separate, the circuit is not conductive ( light off ). NO means Normally Open:when the magnet separate, the circuit is not conductive( light on );When the magnet together, the circuit is conductive ( light off ). Designed for use with alarm systems. Great for use in family and factory window, door. etc. specification: 1. Product Name: Magnetic Door Contact Reed Switch 2. color: White 3. Material: fireproof ABS protection 4.Connection mode: N.C./N.O connection type 5. Rated current: 500 (mA) 6. Rated voltage: (VDC) 100 7. Operating distance: greater than 15 mm, less than 25 mm 8. Rated power: 10W 9. Size: 55 * 12.5 * 11.5 mm 10. Mounting hole size: 7 x 2.5 mm / 0.28 inch x 0.1 inch (length x width) Screw Mounted for easily install Package Content: 2 Sets x MC-31B Magnetic Door Contact Reed Switch 100 Percent SATISFACTION : If you don't absolutely love them let us know and we will refund your purchase price NO QUESTIONS ASKED! We are so confident you will love our products. Have our worry-free 90-day and friendly customer service; This is our confidence in product quality and commitment to customers.