Whether Tuning Your Vehicle For Maximum Performance Or Monitoring Your Driving For Maximum Fuel Economy, Autometers Mechanical Vacuum Gauge Has Been The Solution Trusted By Professionals For Years. An Ultra Precise Bourdon Tube Meter Movement Sits At The Heart Of This Instrument, Providing The Kind Of Accuracy And Durability Necessary To Compete At The Highest Levels. A Simple 1/8" Npt Fitting On The Back Makes Installation Easy, And 1/8" Nylon Line And Fittings Are Included.