The Performance W1338 9-Piece External Star Bit Socket Set fits both 1/4-inch and 3/8-inch drives. Features: * Heat-treated alloy steel * Polished chrome-plated finish * 1/4-inch drive sizes: E-5, E-6, E-7, E-8 * 3/8-inch drive sizes: E-10, E-12, E-14, E-16 * 3/8-inch female to 1/4-inch male adaptor * Bonus storage rail What"s In The Box: * Four 1/4-inch Drive Star Bit Sockes - E-5, E-6, E-7, E-8 * Four 3/8-inch Drive Star Bit Sockets - E-10, E-12, E-14, E-16 * 3/8-inch Female to 1/4-inch Male Adaptwr * Bonus Storage Rail