The Milwaukee 11 pc. 3/8 in. drive metric hex bit socket set with four flat sides is 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. This set includes a storage rail for better organization. Laser engraved size markings provide easy identification and chrome plating offers rust and corrosion protection.