Accurate temperature control of the bluing bath is absolutely a must for long lasting, true-color blue jobs. Brownells stainless steel Bluing Thermometer is carefully sealed for use in the caustic bluing bath. Each and every thermometer is calibrated and double-checked for accuracy. Cheap, poorly constructed thermometers cause more bluing failures than any other single thing, and it is our feeling that any company offering them for sale to gunsmiths has little knowledge of the bluing game. Brownells Bluing Thermometer has a long, 6'''' stem. Only 3'''' of the stem need to be immersed in the bath, leaving 3'''' of safety margin to keep the dial out of the salts. Supplied with a Cl Mfg: Brownells SPECS: Thermometer: Black numbers, silver face. 2-1/8;'''' (5.4cm) diameter, 50Â°-400Â° F. Clip: Stainless Steel. 2Â½'''' (6.3mm) long.