Dive Rite SPG Mini Tech 2" No Hose/Boot, PSINaked gauge has a 2 inch diameter with a 1. 75 inch face (RG2762 NH). A Bourdon tube gauge, the Tech SPG is calibrated to 5000 psi in 100 psi increments for the highest level of accuracy. A tempered glass face is impact and scratch resistant, while the luminescent dial makes it easier to read in low light situations. Comes standard as a naked SPG with a spool to attach a hose swivel to the gauge. A boot is available as a separate option, if desired.