PMD Products .22 CAL and .17 CAL Rifle Chamber Hone Flex-Hone 800 grit 8" Long 800 Grit Flex-Hone Chamber Hone is used to restore the chamber area of your rifle 3" along shaft abrasive part and are 8"OAL. Flex-Hone part number 08305 800 Grit aluminum oxide for final chamber finish The stem wire is covered with a protective shrink tube coating to protect the chamber