The Raychem RTD-200 is a three-wire, ambient sensing platinum RTD (resistance temperature detector-tor) typically used with electronic control systems that require accurate ambient temperature sensing. The RTD-200 comes with a 1/2 in. NPT fitting that installs to the appropriate conduit box. This allows mounting of the RTD in a typical ambient location. This also allows for splicing of RTD extension wire back to the controller.