The G.A.L. Gage Co. Cat # 17 Pipe Pit Gauge GAL-17 is an instrument that will give long life in the field or factory. Range is 0 to 1/2" in 1/64 &.020 increments. Arm can be locked in place at any dimension. All Stainless Steel Gage will fit in shirt pocket and comes in a pocket protector. Has handy formulas on front and decimal equivalents on back