Style SGTHR 19-4 Cut-Off Tool Holder-Gtn-3 (2203-1940) ~ Shank size is 3/4 X 1/2″. ~ Insert width is .160″. ~ Use with GTN-4 inserts which are not included. ~ Maximum work diameter is 1.38″. ~ T-Cut style is the original self-grip. ~ High reliability, rigidity and stability. ~ Superior straightness of cut.