0.3651"-0.5100" (9.28Mm-12.95Mm) Tool Steel Class Zz No-Go (Plus) Ring Gage. Class Zz, Bright Tool Steel, No-Go (Plus) Custom Steel Ring Gage. Perfect For Use As Masters For Bore Gages And Internal Micrometers. Use Vermont Gage Ring Gages To Efficiently Inspect External Dimensions Of Manufactured Parts. With A Go And Nogo Ring, An Inspector Can Quickly Pass/Fail Parts Without Taking Time Consuming Readings From An Indicator. Available In Master (Bi-Lateral Tolerance), Go (Minus Tolerance) Or No-Go (Plus Tolerance). Nist Traceable. Certificate Of Accuracy Included. Vermont Gage Usa Part #231505210. At Checkout, In The 'Additional Instructions' Field, Specify The Ring Gage Inside Diameter Within The Range Specified.