Seco-Larm
Seco-Larm Usa SM-4201-LWQ Wide Track-Mount Overhead-Door Magnetic Contact
Best heavy-duty security sensor for industrial overhead garage doors.
The Seco-Larm SM-4201-LWQ is a robust magnetic contact engineered specifically for overhead doors, accommodating wider gaps up to 3 inches (76mm). It features a rugged aluminum housing, ensuring IP65 weatherproof protection suitable for various environments. The internal contact uses iridium plating for enhanced power handling and extended operational life. Connection is secured via 36-inch armored leads, and the unit supports SPST closed-loop circuits. This contact is highly adjustable, fitting door channel widths between 2-5/8" and 4", and includes a necessary mounting bracket for installation.
$20.94
More Magnetic Contacts Options
Owner Satisfaction
4.7
/ 5
Category Rank
1
/ 61
Best Security System Sensors
Price vs Category Average
-78%
Below average
Gap
376
/ " (mm)
Who it's for
- Installers seeking a quick setup on standard garage tracks
- Homeowners needing reliable security for shifting or heavy doors
- Facility managers requiring durable hardware for harsh industrial environments
Who should skip it
- DIYers wanting to avoid complex cable routing and wiring
- Design-conscious owners preferring discreet or hidden security components
- Users with custom or non-standard industrial door track systems
Performance breakdown
Gap Tolerance
Three-inch operating gap handles industrial overhead doors with ease.
Build Durability
Rugged aluminum housing withstands harsh environments and physical impact.
Weather Resistance
IP65 rating ensures reliable performance against dust and water ingress.
Installation Versatility
Adjustable bracket accommodates a wide range of door channel widths.
Contact Longevity
Iridium plating significantly extends the operational lifespan of the internal switch.
Cable Protection
Armored leads provide essential defense against fraying and accidental damage.
Key Specs
Gap
3" (76mm)
Type
SPST, Closed Loop
Cable
36" Armored cable, 2 Wires
Adjustable for door-channel widths
2-5/8" to 4" (66 to 101 mm)
Mounting Type
Track-Mount
Sensor Type
Magnetic Contact
Connectivity Type
Wired
IP Rating
IP65 Weatherproof
Features
- Wide 3" gap ideal for overhead doors
- Rugged aluminum housing with IP65 weatherproof rating
- Iridium-plated contact for longer life
- Adjustable for 2-5/8" to 4" channel widths
- Armored cable protects wire leads
- Utilizes reliable closed-loop circuits
- Mounting bracket included for easy setup
What customers say
Customers highly value the Seco Larm SM 4201 LWQ for its exceptional reliability in demanding overhead and commercial door applications. The core praise focuses on its robust construction and superior wide gap capability, which effectively prevents false alarms from vibration or minor door shifts that plague standard contacts. Professionals appreciate the durable, heavy-duty build, confirming it offers long term dependability. While track mounting requires careful alignment for some, the consistent, flawless performance once installed justifies the effort. This contact is viewed as a professional grade component, delivering dependable security monitoring where lesser products fail. Users feel the premium price is warranted for guaranteed peace of mind.
Know before you buy
Yes, this sensor is specifically designed for overhead doors. It is ideal for residential or commercial garage doors where the gap between the door and the frame is wider than a standard contact can handle.
Yes, the SM-4201-LWQ features a rugged aluminum housing with an IP65 weatherproof rating, making it suitable for outdoor environments and exposure to the elements.
This model supports a wide gap of up to 3 inches (76mm), which is significantly larger than typical magnetic contacts, ensuring reliable operation even if the door alignment shifts slightly.
Yes, the unit includes an adjustable mounting bracket that fits door channel widths ranging from 2-5/8 inches to 4 inches, allowing for a precise fit on most overhead door tracks.
Iridium plating is used to enhance power handling and prevent oxidation, which significantly extends the operational life of the contact compared to standard materials.
This is a standard SPST closed-loop magnetic contact. It is compatible with most wired security systems that support normally closed (NC) contact inputs.
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