1. Valve Seat Grinding Stones Set Of 36 Pieces For Sioux Holder 11/16" Thread 2. Set contains each of the following Sizes: Stone Sizes Stone Sizes 2.1/2"" - 3 PCS ,2.3/8"" - 3 PCS ,2.1/4"" - 3 PCS, 2"" - 3 PCS , 1.7/8"" - 3 PCS, 1.3/4"" - 3 PCS,1.5/8"" - 3 PCS, 1.1/2"" - 3 PCS, 1.3/8"" - 3 PCS, 1.1/4"" - 3 PCS, 1.1/8"" - 3 PCS 1"" - 3 PCS 3. The Stones can be dressed to any angle with Thread Intact. 4. We made heavy duty stones of thread size of 11/16"". 5. Verified Bond 80 Grit medium aluminium oxide pink Stones.