SK 4668, 3/8 inch Drive, SAE, Standard Depth, Universal Spline, 8 Piece Socket Set (5/16-7/8 inch) Made in USA! Universal spline design works on 6 types of fasteners Superkrome finish provides long life and maximum corrosion resistance Lifetime warranty by SK Tools. Made in USA Includes sizes 5/16, 3/8, 7/16, 1/2, 9/16, 3/4, 13/16, and 7/8 inch These are professional grade tools