Description Warranty Information We recommend the use of a TW-Thermowll in conjunction with a bimetallic thermometer when the application involves a corrosive medium, high pressure, or high flow velocity. Perfect for applications requiring protection for unarmored liquid-in-glass test thermometers, or other temperature sensing elements with a maximum diameter of .25. These #20 gauge bimetallic thermowells meet or exceed SAMA specifications and are also available in heavy duty, flange, socket weld, and Van Stone models. Standard thermowells are made of 316L SST and are stepped to 1/2 OD, except for 2½" insertion. Materials of construction iis 316L stainless steel (standard),Thermowell,General Use Heavy Duty 4" Stem, Specification Sheet This product comes with a 1 year Warranty