Large, easy-to-read 3-18 inch gauges feature steel cases with polycarbonate crystal and with color-coded scales dials with 1% accuracy (class 1) full scale movement provide the level of accuracy necessary for critical charge systems sliding double O-ring pistons reduce wear long life nylon seats forged brass body for durability full-size metal valve handles make for easy operation full porting maximizes capacity and flow this unit includes color-coded, 60 inch Plus II hoses with compact ball valve end fittings hose assemblies UL recognized for 4000 psi (275 bar) burst and 800 psi (55 bar) working pressure made in the USA.