Door reed contact sensor BLOW HO-03L 4924# white — magnetic door/window sensor

Wired magnetic reed door/window sensor BLOW HO-03L in white is a compact magnetic contact switch designed to detect opening and closing of doors and windows. The sensor consists of a main body and a magnet that create a normally closed or normally open contact depending on installation. It is intended for surface mounting and wired connection to alarm systems, access control panels or other security monitoring equipment where a simple, reliable magnetic contact input is required.

Advantages

The sensor offers a small footprint and discreet appearance for unobtrusive installation on frames and sashes. Its wired design provides a stable, low-latency signal to control panels without the need for batteries, ensuring continuous operation. The device is compatible with standard alarm inputs and requires only basic wiring, which simplifies integration into existing security systems. The durable plastic enclosure resists common mechanical wear associated with door and window movement.

Suitable for

• Residential doors and windows for intrusion detection
• Commercial access points such as offices and storage rooms
• Integration with wired alarm systems and control panels
• Perimeter monitoring in retail and small business premises

Key specifications

• Type: Wired magnetic reed contact sensor
• Color: White
• Mounting: Surface mount on door or window frame
• Contact type: Magnetic reed switch (normally closed or normally open depending on wiring)
• Body material: Rigid plastic enclosure suitable for indoor use
• Connection: Two- or three-wire terminal connection for alarm inputs
• Sensing method: Magnet proximity activation

How to use

Position the main sensor body on the fixed frame and align the magnet on the moving sash or door so that the two parts meet within the specified gap when closed. Secure both parts with screws or adhesive as appropriate for the surface. Connect the sensor leads to the control panel input following the panel manufacturer’s wiring diagram; select normally closed or normally open configuration according to system requirements. Test the installation by opening and closing the door or window to confirm the control panel registers the change of state.

Usage recommendations

Install the sensor indoors or in sheltered locations to avoid direct exposure to weather. Maintain an appropriate gap between sensor and magnet as specified by the installer’s guide to ensure reliable switching. Route wiring to avoid pinching or sharp bends and secure connections inside the control panel. Periodically inspect mounting and wiring for signs of wear or loosening and retest operation after any maintenance.