VALVE SEAT GRINDER STONES + HOLDER / CARRIER + PILOTS + DRIVE BALL HIGH PERFORMANCE  STONES SOUND LESS MOTION HOLDER STONE SIZES :- 2", 1-3/4" , 1-1/2" , 1-3/8" STONE THREAD - 11/16" 2PC PILOT   11/32'' &  3/8'' OPTIMUM FOR SIOUX STONES AND PILOTS SIZE CAN BE MODIFY AS PER REQUIREMENT