This thermowell threads into any 1/2" FPT fitting.  It has a 4" penetration from the face of the threads to the tip of the thermowell. The thermowell tube extends 4" to the outside of the fitting and is surrounded by a .75" OD heat shield.  This thermowell is designed to protect your sensor cable from the heat wash of a gas burner and help give a more stable reading. Made from 304 stainless and has a brushed polish finish.