--- product_id: 215605131 title: "MC-31B Magnetic Reed Switch Door Sensor, Surface Mount Magnetic Door Switch NC NO Normally Open Closed, Wired Magnetic Switch for Home Security Alarm System, Reed Switch Normally Open," brand: "takhrwod" price: "S$18" currency: SGD in_stock: true reviews_count: 13 category: "Takhrwod" url: https://www.desertcart.sg/products/215605131-mc-31b-magnetic-reed-switch-door-sensor-surface-mount-magnetic store_origin: SG region: Singapore --- # Supports up to 12V DC, 10W power Dual NC/NO contact modes Trigger range 10-20mm magnetic sensing MC-31B Magnetic Reed Switch Door Sensor, Surface Mount Magnetic Door Switch NC NO Normally Open Closed, Wired Magnetic Switch for Home Security Alarm System, Reed Switch Normally Open, **Brand:** takhrwod **Price:** S$18 **Availability:** ✅ In Stock ## Summary > 🛡️ Elevate your security game with smart magnetic precision! ## Quick Answers - **What is this?** MC-31B Magnetic Reed Switch Door Sensor, Surface Mount Magnetic Door Switch NC NO Normally Open Closed, Wired Magnetic Switch for Home Security Alarm System, Reed Switch Normally Open, by takhrwod - **How much does it cost?** S$18 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.sg](https://www.desertcart.sg/products/215605131-mc-31b-magnetic-reed-switch-door-sensor-surface-mount-magnetic) ## Best For - takhrwod enthusiasts ## Why This Product - Trusted takhrwod brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Precision Magnetic Trigger:** Detects door/window status with a 10-20mm sensing range, ensuring accurate alerts. - • **Durable Anti-Fire ABS Build:** Crafted from fire-resistant ABS material for long-lasting safety and resilience. - • **Versatile Dual-Mode Contacts:** Seamlessly switch between Normally Open and Normally Closed for custom security setups. - • **Easy Surface Mount Installation:** Includes screws for quick setup on wooden doors or windows—security made simple. - • **Robust Voltage & Power Handling:** Operates reliably within 5-12V DC and up to 10W power, perfect for low-voltage alarm systems. ## Overview This 2-pack Magnetic Reed Switch set offers flexible Normally Open/Closed contact modes, supporting low-voltage DC 5-12V systems with up to 10W power. Designed with a 10-20mm magnetic trigger range and housed in durable anti-fire ABS, these switches are ideal for enhancing wired alarm systems on doors and windows. Easy to install with included mounting screws, they provide reliable theft deterrence and seamless integration for professional-grade home or office security. ## Description Product description MAGNETIC REED SWITCH INSTALLATION INSTRUCTIONS 1:The door and window magnet should be installed at the closed position of the door/window 2:The magnet part is installed on the movable door and window. The switch part is installed on the fixed door and window frame. The switch part and the magnet part should be aligned as much as possible. 3:The door magnet should be away from the strong magnetic field interference source such as a transformer. Otherwise, the working characteristics of the door magnet will be changed and possible wrong actions. 4:Magnetic Contact sensors can be added to an existing wired Alarm Systems. 5:They are ideal for protecting doors, windows and patio doors and any opening device such as a drawer or cupboard for example.In the event of no contact the alarm will be activated immediately.Magnetic Contacts are perfect for use in situations where it is not suitable to fit PIR sensors, for example where there are pets or animals. 6：Recommendations in application: wooden door, window, metal doors, gates and any other compatible application. N.C. / N.O. DEFINITION N.C. means Normally Closed: When the magnet together, the circuit is conductive( light on ); When the magnet separates, the circuit is not conductive ( light off ); N.O. means Normally Open: When the magnet separates, the circuit is conductive( light on ); When the magnet together, the circuit is not conductive ( light off ). Please check the right need carefully before purchasing it! PRECAUTIONS 1:It can only provide a switch signal to the device, which cannot directly load the power, nor directly connect the lamp! 2:The door magnet should be away from the strong magnetic field interference source such as a transformer. Otherwise, the working characteristics of the door magnet will be TECHNICAL SPECIFICATIONS Review: Half worked - Only one of the two worked. One was shipped broken. Review: Great switch - Used to create wired switch for garage door - I purchased this to make my own wired open/close detector for my garage door opener. The ability to use this both as a Normally Open or Normally Closed switch is great because I wasn't sure what mode I needed to have for my plan to work. So far it has worked flawlessly for me. ## Features - Reliable Magnetic Reed Switch Performance This MC-31B magnetic reed switch provides stable and accurate detection for doors and windows. The magnetic switch ensures consistent signal transmission for home security and alarm systems. - NC / NO Flexible Configuration Supports both normally closed (NC) and reed switch normally open (NO) modes. The magnetic door switch allows flexible installation based on your alarm system requirements. - Durable Fireproof ABS Material Made of high-quality fireproof ABS, this reed switch is designed for long-term use. Strong, heat-resistant, and suitable for both residential and commercial environments. - Ideal for Security Alarm Systems This magnetic door switch is widely used in burglar alarm systems, smart home setups, and access control systems. Perfect for wooden doors, windows, cabinets, and gates. - Easy Surface Mount Installation Surface mount design with included screws for quick installation. Package includes 2 sets magnetic reed switch and 8 screws for secure mounting. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B086GYJLML | | Actuator Type | [POSSIBLE] Plunger | | Best Sellers Rank | #42,806 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #9 in Reed Switches | | Brand | TAKHRWOD | | Brand Name | TAKHRWOD | | Circuit Type | 2-way | | Color | black | | Connectivity Protocol | X-10 | | Connector Type | Screw Fixation | | Contact Material | Plastic | | Contact Type | Normally Open and Normally Closed | | Control Method | App | | Current Rating | 500 Milliamps | | Customer Reviews | 4.3 out of 5 stars 739 Reviews | | International Protection Rating | IP65 | | Item Weight | 0.01 Ounces | | Manufacturer | TAKHRWOD | | Material Type | Plastic | | Model | 31B | | Mounting Type | Door Mount | | Number of Positions | 1 | | Operating Voltage | 12 Volts | | Operation Mode | ON-OFF | | Part Number | B3 | | Switch Type | Spst-no/Nc | | Terminal | Screw | | UPC | 779172986510 | | Unit Count | 2 Count | | Wattage | 10 watts | ## Product Details - **Brand:** TAKHRWOD - **Circuit Type:** 2-way - **Connector Type:** Screw Fixation - **Contact Type:** Normally Open and Normally Closed - **Current Rating:** 500 Milliamps - **Material:** Plastic - **Operating Voltage:** 12 Volts - **Operation Mode:** ON-OFF - **Switch Type:** Spst-no/Nc - **Terminal:** Screw ## Images ![MC-31B Magnetic Reed Switch Door Sensor, Surface Mount Magnetic Door Switch NC NO Normally Open Closed, Wired Magnetic Switch for Home Security Alarm System, Reed Switch Normally Open, - Image 1](https://m.media-amazon.com/images/I/51-rYaop8UL.jpg) ![MC-31B Magnetic Reed Switch Door Sensor, Surface Mount Magnetic Door Switch NC NO Normally Open Closed, Wired Magnetic Switch for Home Security Alarm System, Reed Switch Normally Open, - Image 2](https://m.media-amazon.com/images/I/61L2sb83TqL.jpg) ![MC-31B Magnetic Reed Switch Door Sensor, Surface Mount Magnetic Door Switch NC NO Normally Open Closed, Wired Magnetic Switch for Home Security Alarm System, Reed Switch Normally Open, - Image 3](https://m.media-amazon.com/images/I/61NlK6sqM7L.jpg) ![MC-31B Magnetic Reed Switch Door Sensor, Surface Mount Magnetic Door Switch NC NO Normally Open Closed, Wired Magnetic Switch for Home Security Alarm System, Reed Switch Normally Open, - Image 4](https://m.media-amazon.com/images/I/51QHVhcZQ1L.jpg) ![MC-31B Magnetic Reed Switch Door Sensor, Surface Mount Magnetic Door Switch NC NO Normally Open Closed, Wired Magnetic Switch for Home Security Alarm System, Reed Switch Normally Open, - Image 5](https://m.media-amazon.com/images/I/51TG1wyfuvL.jpg) ## Available Options This product comes in different **Color** options. ## Questions & Answers **Q: What is the magnetic gap (distance) at which these will close contacts?** A: The switch I have will work up to 1 inch away. This is measured with both pieces flat on a table and moving them apart until the reed switch stops seeing the magnet. **Q: Will these work to turn on/off LED light strips?** A: They should.All depends how you would set them up.The switch is normally used on doors and windows. **Q: What wire is recommended for use with this? Looking to wire up a light in my small toolbox.** A: 18 AWG Wire **Q: can i use this for 110v?** A: Not directly. You will need a relay that reduces the power going to the magnet. My experience is that even with 12v power supply, if the power is more that 500ma, this switch will fail. They work great, just not rated to take much current. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Half worked *by T***M on June 3, 2023* Only one of the two worked. One was shipped broken. ### ⭐⭐⭐⭐⭐ Great switch - Used to create wired switch for garage door *by M***T on July 21, 2023* I purchased this to make my own wired open/close detector for my garage door opener. The ability to use this both as a Normally Open or Normally Closed switch is great because I wasn't sure what mode I needed to have for my plan to work. So far it has worked flawlessly for me. ### ⭐⭐⭐⭐ It will not melt if you use it right. *by K***Y on January 1, 2024* I found this magnetic switch and it was more-or-less perfect for my application, but I couldn't help but notice all of the reviews of melted units. On further inspection you'll notice that many of these reviews detail misuse of the product by passing far too much current through it, for example to a lightbulb. This item uses a lightbulb as an example but explicitly says it should run to some sort of panel. This is a switch meant for powering a relay that can actually handle the current of your application. This is a switch for a signal, not for power. This will work great for something like an Arduino, but it will not for powering truck lights. Be warned that this is totally a Chinese wholesale product and you probably cannot pass through as much current as it says, but using it modestly will yield the intended result. Realistically you should not pass through 0.5A. You don't need much for a signal. ## Frequently Bought Together - 2X Magnetic Reed Switch Normally Open Closed NC NO Door Alarm Window Security/Magnetic Door Switch/Magnetic Contact Switch/Reed Switch, DC 5Vto12V Light (Black) - ECO-WORTHY Linear Actuator Motor Controller, Remote Positive Inversion Control Kit for Linear Actuator, Forward Reverse Remote Control System 12V DC - ECO-WORTHY Heavy Duty 330lbs/1500N Solar Tracker Linear Actuator Multi-Functions with Mounting Brackets (12V, 4") IP54 Waterproof Linear Motion Actuator --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.sg/products/215605131-mc-31b-magnetic-reed-switch-door-sensor-surface-mount-magnetic](https://www.desertcart.sg/products/215605131-mc-31b-magnetic-reed-switch-door-sensor-surface-mount-magnetic) --- *Product available on Desertcart Singapore* *Store origin: SG* *Last updated: 2026-05-18*