Resideo 7939WG-GY MPS20 Surface Mount Magnetic Contact with Terminals, 1-1/4" Gap, SPST, Gray

Protect doors and windows with a compact, dependable surface-mount sensor designed for professional security systems. The Resideo 7939WG-GY MPS20 surface mount magnetic contact delivers consistent, tamper-resistant monitoring for residential and commercial applications. Featuring a SPST (Normally Closed) reed switch and a standard 1-1/4" (32 mm) gap, this contact ensures accurate trip detection while the concealed end-of-line (EOL) resistor keeps wiring tidy and resistant to tampering. Surface-mount installation is flexible—use screws or double-sided adhesive to speed deployment, and wire multiple contacts in series on a single zone to reduce panel I/O and simplify system design. Rated to operate in extreme cold down to -40°F, the gray housing blends into door and window frames for unobtrusive protection. Ideal for perimeter security, alarm monitoring and integration with surveillance systems, the Resideo 7939WG-GY offers installers a reliable, low-cost sensor that improves overall system performance. Add this magnetic contact to your wired security and surveillance setup today to streamline installation and strengthen monitoring coverage.

• Discreet, professional appearance with concealed end-of-line (EOL) resistor for clean installations and tamper-resistant aesthetics
• Fast surface-mount installation using screws or double-sided adhesive—reduces labor and downtime on retrofit and new-build projects
• Reliable perimeter protection with a SPST (Normally Closed) reed switch and a standard 1-1/4" (32 mm) activation gap for accurate door/window monitoring
• Supports multiple contacts wired in series on a single zone to simplify wiring and lower panel input requirements
• Built to perform in harsh environments with low-temperature operation down to -40°F, ideal for indoor and semi-protected outdoor openings
• Neutral gray finish blends into most commercial and residential settings for unobtrusive surveillance integration