Application Thermowells for temperature instruments are recommended for all process systems where pressure, velocity or viscous, abrasive and corrosive materials are present individually or in combination. A properly selected thermowell will protect the temperature instrument from possible damage resulting from these process variables. Furthermore, a thermowell permits removal of the temperature instrument for replacement, repair or testing without effecting the process media or the system. Process Connection: External means to connect thermowell to process piping system. Wells can be threaded, bolted (to matching flange), clamped or welded in place. Bore Diameter: Dimension of internal bore to match the diameter of the instrument stem/bulb inserted into the well. The 0.260" sizes fit instrument stem/bulb diameters of 1/4" and 3/8" respectively. Bore length equals "S" dimension. Reduced Shank: Also called reduced tip. The shank OD is reduced over the last 2-1/2" of the "U" dimension from the standard root diameter to a 1/2" OD.