7/8" (22MM) Flex Hone 400 Grit Aluminum Oxide 7/8" Cylinder Flex-hone for all bore applications utilizing a 0.830" to 0.885" or 21mm to 23mm bore. Perfect for Bronze Chevy lifter bores and general refinishing. Hone is self centering , Hone tool can be used with a 3/8" or 1/2" chuck portable drill This patented Flex-Hone is the best way to create a Cross Hatch surface finish with suspended globule working abrasives.