The 5816OD is Honeywell's version of the standard indoor 5816WMWH
indoor wireless contact. The 5816OD is dual purpose just like the 5816WMWH. The 5816OD has two loops. You can, along with the included magnet, use this as a door contact for outdoor entrances such as gates, storage sheds, etc. Not only can you use it like that, but you can wire NC 2 wire devices into the screw terminals on the inside of the 5816OD's case. This sensor is compatible with the Honeywell Vista 15P, Vista 20P and all Lynx Series.