The M-4750 is a 0 - 300 PSI liquid dilled pressure gauge that has a front O.D. of 3 1/8", glass face diameter of 2 7/8",ABSl case fits a hole size of 2 3/4" O.D.. This guage is a center back mount with a 1/4" NPT threaded connection. A U clamp bracket is included for mounting to a panel. Can be used with our M-151-A gauge bracket panel. (Image shown is a 0 - 200 PSI Liquid Filled Pressure Gauge.)