The Milwaukee Quik-Lok Bit system allows users to change drilling and driving accessories quickly and easily. The patented all-hex chuck feature will accept and hold all 3/8 in. and 1/2 in. hex shank accessories including double-ended bits. The kit is an ideal choice for professional contractors with the need to frequently and quickly change bits. Other system features include titanium drill bits for long life and superior performance, screwdriver bits made from premium quality S2 steel for high torque applications, and a convenient storage case. Designed for quick change applications Crafted from high grade S2 tool steel which provides excellent wear resistance for long life