Milwaukee's Hex Bit Sockets with FOUR FLAT™ sides are designed from the ground up to be part of the most versatile socket family. Milwaukee® bit sockets feature an innovative design with four parallel flat sides, which deter rolling and are wrench-compatible. This also creates a slim profile to provide the best access in tight spaces. The one-piece socket design offers improved durability compared to two-piece designs by eliminating the risk of the bit separating from the socket base. Laser engraved size markings provide easy identification and chrome plating offers rust and corrosion protection. All Milwaukee® bit sockets are backed by a Lifetime Guarantee.