Milwaukee® SHOCKWAVE™ Impact Duty™ ECX™ driver bits are engineered for extreme durability and up to 10X life. ECX™ driver bits are a combination of Phillips®, square recess and slotted tips designed for superior grip to eliminate rounding out fastener heads. Made from proprietary steel and heat treated to control hardness, the SHOCKWAVE™ Impact Duty™ ECX™ driver bits feature an innovatively designed geometric shock absorption zone to extend life. The forged tip allows for a secure grip and maximum contact eliminating stripping or slipping. Milwaukee® SHOCKWAVE™ Combo Power Bit Kit, Single Ended, 2 Piece, Specifications: 2 in L, 1/4 in Hex Shank, Carbon Steel, Black Oxide