Century Drill And Tool 31 Piece S2 Screwdriver Bit SetScrewdriving bits made from premium S2 steel for long tool life while driving common, mild steel screws or case hardened screws 1 4 Inch power drive shank fits all power screw guns cordless screwdrivers variable speed electric drills and quick change adapter 21 piece screwdriver bit set contains insert bits 2 #1 Philips 5 #2 Philips 2 31 square 5 #2 square 1 #4 5 slotted 3 #6 8 slotted 2 #8 10 slotted 1 #10 12 slotted 1 each T15 T20 T25 T27 T30 star