Plain Plug Gauge for ID in Jig Body Go 10 to 10.001 Cyl. 0.0001 Len. 55 to 56 with tapping of M4 NOGO 10.014 to 10.015 Cyl. 0.0001 Len. 10 to 11 / Std. Gauging area should have lapped finish. Gauge No. PPG 10000.10015