Shotgun Barrel Flex-hone 20 Gauge Ga 180 Grit 34" Length Flex-Hone tools will restore your shotgun barrel by abrasively surface finishing the barrel bore 3" along shaft abrasive part, tool is 34" long w/ tool stem covered to protect barrel 180 Grit silicon carbide for initial barrel refinishing Only fits 20 gauge gun barrels Unique fingers gently smooth the metal, creating a more uniform surface that resists wear, corrosion and reduces fouling