The 1/4" Burr Bolt Removal Kit, No. CBBR-KIT1, from Mac Toolsis designed to remove broken studs and reduce damage to existing threaded holes.The tool is CNC machined for consistent quality and aims to maximize the potential of drilling threads on the center. Included in this kit is the BR Countersink 1/4-20, No. CBCS1, the BR Drill 1 /4-20 and 5 /16-18, No. CBDR1, the BR Endcut Bur 1 /4-20, No. CBECB1.