Vacuum gauges assure accurate readings of line vacuum and provide constant monitoring for maximum herd protection. Dial is 2-5/8" in diameter and gauge is threaded for 1/4” NPT bottom mount and has a stainless steel cover. Factory calibrated for accuracy. Dual scale Hg and KPA. Glycerine fill assures accuracy by providing a cushion against vibration. Wt. 8 oz.