4" Engine Cylinder Adjustable from 2-1/4"-7" Hone 3 blade stone Set includes 100 GRIT , 220 GRIT AND 320 GRIT STONES ATTACHED TO EXTRA HONE ARMS(5/8" wide) 3 Blade Stone Hone 80, 240, 320 grit Aluminum Oxide Stones, 4" long x 5/8" wide (larger than most) Hone designed to expand from 2" Diameter Bore to 7" Diameter Bores Bore Restoration and clean-up, 80 grit De-glazing 240 grit (stock ring-set) De-glazing 320 grit (Racing Moly or Chrome faced ring-set) Protective Collar prevents stone breakage and controls force of tool on cylinder walls Flexible shaft improves tool centering and alignment Fits 3/8" or 1/2" chuck portable drills or drill presses Tension adjustment knob for controlled cut If used in rigorous motion can provide 45 degree cross hatch Tool is plated for long life and nice appearance Grinding stone with holder dimensions: 4 " L, 5/8" W, 5/16" H Overall dimensions: 12 1/4" L x 7 1/4" W x 1 13/16" diameter (closed storage diameter)