BRAND NEW HEAVY DUTY SIUOX 1702 BB STYLE 2x VALVE SEAT GRINDER STONE HOLDERS ALONG WITH 2x STAR DRIVE TERMINAL Equipped C3 Series Dual  High Speed Bearings THREAD 11/16" x 16 Tpi 0.385"  Pilot Center Bore  BLACK & DECKER,SIOUX VALVE GRINDER PILOT AND GRINDER STONES IN OUR EBAY SHOP BULK QUERY CONTACT US ! FEEL FREE TO ASK ANY QUESTION THANKS FOR LOOKING ! For Bulk Purchase do email us at " Ask the Seller question" We do Custom job  Thanks