Stainless Steel Thermowell with 1/2" Male NPT Threading and Heat Shield. This thermowell threads into any standard 1/2" female NPT fitting. Features a 4" shielded tube on the outside end as a heat shield, 3/4" outer diameter. This helps protect wires or cables from heat source (such as a burner), also assures accurate temperature reading at the probe end. 4" probe from the face of the threads to the tip assures good reach without too much intrusion. Overall length is 9". Comes with washer, o-ring and nut.