Autometer Cobalt 52mm 20psi mechanical Boost GaugeThe Standard In The Industry, Autometers Mechanical Boost Vac Gauges Have Found Their Way Into More Builds Than Any Other. Using A Patented, High Precision Bourdon Tube Meter Movement, There Isnt Another Gauge On The Market That Can Lay Claim To The Levels Of Accuracy Or Durability You" Ll Find Here. A Simple 1 8" Npt Pressure Connection Requires No Electrical Hookup For Operation. Includes 1 8" Npt Fittings And Nylon Line Kit.