Name: MC-38 NO+NC Feature: 1. Work as an anti-theft alarm, ideal for wood door and window. 2. Self-Adhesive Mount, Screw Surface Mount contact, ABS Housing. Long wire lead that can side mounted. 3. There are two types of reed switches: "normally open" reed switches and "normally closed" reed switches. The metal reeds on a normally open switch stay open when there is no magnet near the switch. In the presence of a magnetic field, the contacts of a normally-open reed switch will close. A normally-closed reed switch is closed when it is not near a magnet; as a magnet is brought close to it, a normally-closed switch will open. Specifications: Material: ABS Voltage: 100V DC Rated power: 10W Actuation distance: 15-25mm Dimension: approx. 55*12.5*11.5 mm / 2.17 inch x 0.45 inch x 0.45 inch (L * W * H). Switch pattern: NC/NO , alarm-on-broken Mounting method: SMD (by screws or double-sided tapes) Widely Used - This Door Contact Sensor works with any access control or burglar alarm system available. Note: the Magnetic Door Switch must be installed according to the sensing distance, Door magnetic induction can only provide a switch signal, which can not directly load the power, nor directly connect the lamp! Package Includes: 2 Sets x MC-38 Magnetic Door Window Contact Sensor Warm Tip: Due to manual measurement, there may be a slight error in size. 【Hassle-Free Warranty】: guarantee high quality and good service. Here with our 90-day money back risk-free purchase guarantee, Refund or Replacement for any quality problem.