![Magnetic contact switch (door sensor) : ID 375 : $3.95 : Adafruit Industries, Unique & fun DIY electronics and kits Magnetic contact switch (door sensor) : ID 375 : $3.95 : Adafruit Industries, Unique & fun DIY electronics and kits](https://cdn-shop.adafruit.com/970x728/375-01.jpg)
Magnetic contact switch (door sensor) : ID 375 : $3.95 : Adafruit Industries, Unique & fun DIY electronics and kits
![10pcs 4x28mm Reed Switch Sensor Normally Open Diy Magnetic Reed Switchs Electronic No 4*28mm - Sensors - AliExpress 10pcs 4x28mm Reed Switch Sensor Normally Open Diy Magnetic Reed Switchs Electronic No 4*28mm - Sensors - AliExpress](https://ae01.alicdn.com/kf/HTB1ekNZrv5TBuNjSspmq6yDRVXa8.jpg)
10pcs 4x28mm Reed Switch Sensor Normally Open Diy Magnetic Reed Switchs Electronic No 4*28mm - Sensors - AliExpress
![Reed switch magnetic sensor - MK21P, MK21M Series - StandexMeder Electronics GmbH - for high-temperature Reed switch magnetic sensor - MK21P, MK21M Series - StandexMeder Electronics GmbH - for high-temperature](https://img.directindustry.com/images_di/photo-g/23046-15342028.jpg)
Reed switch magnetic sensor - MK21P, MK21M Series - StandexMeder Electronics GmbH - for high-temperature
![Amazon.com: BQLZR Cylindrical Plastic Mounted Reed Proximity Switch Magnetic Sensor Pack of 2 : Industrial & Scientific Amazon.com: BQLZR Cylindrical Plastic Mounted Reed Proximity Switch Magnetic Sensor Pack of 2 : Industrial & Scientific](https://m.media-amazon.com/images/I/61H8H9b8wHL.jpg)
Amazon.com: BQLZR Cylindrical Plastic Mounted Reed Proximity Switch Magnetic Sensor Pack of 2 : Industrial & Scientific
![Amazon.com: Baomain Magnetic Reed Switch Sensor CS1- S DC10-30V 2.0m Wired Cable : Industrial & Scientific Amazon.com: Baomain Magnetic Reed Switch Sensor CS1- S DC10-30V 2.0m Wired Cable : Industrial & Scientific](https://m.media-amazon.com/images/I/61YaH2PhjuL._AC_UF1000,1000_QL80_.jpg)