Potter / Amseco ODC59B

Works perfectly as a garage door sensor to let me know whether it’s open or closed. I especially like that it can be used in either Normally Open or Normally Closed modes. For my specific application, the internal reed relay needed to be open when the garage door is closed. The 2 inch operating distance makes it easy to install, so much better than others which have to be within 1/8th inch of the magnet.