This Klein nut driver set includes four pieces with drive sizes of 5/16, 3/8, 1/4, and a nut driver. The set also includes Craftsmans 1/2, 7/16, 3/8, and 5/16 drivers. These drivers are made of stainless steel and are perfect for standard (SAE) measurements. The drivers have a five-point drive type and are designed for use with nuts. Made in the United States, this set is ideal for home and garden use or for workshop equipment.