Designed with a 1/4” [0.6cm] shank for use in Jacobs type chucks.This stone chuck accommodates abrasive stones with 1/4” [0.6cm] I.D. arbor only. Manufactured of alloy steel and plated. Unit Dimensions: 2 3/16” long x 3/4” Shank Diameter [6cm x 2cm] with a 1/4”Shank Diameter.