Valve Seat Grinder Stone Holder Sioux And Star Drive With 2 Pilots & 6 Stones Product Specifications: Valve Seat Grinding Stone Holder Sioux & Star Drive with 2 Pilots and 6 Stones Robust Sioux-style valve seat grinding stone holder 1 1/16" thread + 2 pilots (pilot sizes: 5/16" and 1 1/32") + Star drive cone + 6 stones 2 1/4" 2" 1 7/8" 1 3/4" 1 5/8" 1 1/2".
