Wired door and window contact sensor set, 3 pieces, black. Each unit uses a magnetic reed switch to detect open and closed positions and provides reliable, hardwired contact inputs for alarm panels and control systems. Key benefits Simple, dependable detection: Magnetic reed switch responds instantly when the magnet moves away from the sensor, enabling fast and consistent door and window status reporting. Flexible wiring options: Supports both normally open and normally closed wiring to match the logic of most alarm panels and access controllers. Discreet surfacemount design: Lowprofile black housings blend with darker frames and are designed for visible or semiconcealed surface installation. Pack of three: Three sensors included for multiple doors or windows or to cover primary openings around a property. Main features and attributes Function: Wired contact sensor that changes state when the magnet is separated from the reed switch; suitable for security and monitoring circuits. Compatibility: Integrates with most wired security systems, alarm panels, access control inputs, and automation controllers that accept reed contact inputs. Mounting style: Surface mount; designed for straightforward installation on door and window frames or other surfaces where a magnetic contact is needed. Material and finish: Durable plastic housing in black for low visibility and easy maintenance. Performance: Mechanical reed switch provides stable electrical contact with minimal power draw and long service life under normal conditions. Package: Three identical sensor assemblies included to cover multiple points. Typical applications Home security: Monitor doors and windows and feed direct inputs to a wired alarm panel to trigger alerts when an entry point opens. Commercial and utility enclosures: Protect cabinets, meter boxes, server racks, and storage closets by detecting unauthorized openings. Automated systems and DIY projects: Provide a reliable contact input for access control systems, relay logic, and home automation scenes. Why choose this sensor set Hardwired connection avoids battery dependence and reduces maintenance compared to wireless sensors. Supports both NO and NC wiring so installers can match system requirements without additional hardware. Compact, surfacemount form factor fits common installation locations and keeps sensors unobtrusive. What you get Three wired magnetic reed contact sensors in black, surfacemount style, each ready to be wired into existing control or alarm circuitry. Installation notes Intended for surface mounting on a door, window, or frame with the magnet aligned to the reed switch body when closed. Confirm wiring polarity and selected NO or NC configuration with your control panel documentation before finalizing connections.