Screwdriving bits made from premium S2 steel for long tool life while driving common or mild steel screws or case hardened screws. Fits multiple tip hand drivers and 1/4-Inch hex holders for power driving applications. Always use a bit holder for power driving applications. 7 Piece Set includes hex key bits in 5/64-Inch , 3/32-Inch , 7/64-Inch , 1/8-Inch , 9/64-Inch , 5/32-Inch , and 3/16-Inch.