Plain Plug Gauge for ID in Jig Body Go 6 to 6.001 Cyl. 0.0001 Len. 35 to 36 with tapping of M4 NOGO 6.011 to 6.012 Cyl. 0.0001 Len. 10 to 11 / Std. Gauging area should have lapped finish. Gauge No. PPG 6000.6012 