The Bostitch BSA218DGM 18-Piece Drive Guide Set features a compact magnetic drive guide which reduces wobble. This set is designed with shock resistant steel for longer life, and is heat treated to reduce breakage and wear. Hex shank is 1/4-inch. Set Includes: (1) Compact Magnetic Drive Guide, (1) 1-inch PH1 bit tip, (1) 1-inch SL8 bit tip, (7) 1-inch PH2 bit tip, (2) 1-inch T25 bit tip, (1) 1-inch SQ1 bit tip, (2) 1-inch SQ2 bit tip, (1) 1-inch SQ3 bit tip, (2) 2-inch PH2 bit.