The BlueSpot Tools 3/8in Drive Spline Sockets are manufactured from chrome vanadium steel for added strength and durability. These sockets can be used on a range of fasteners 6pt, 12pt, star and square. Supplied on rail. These 10 sockets cover the following sizes- Metric 7, 8, 9, 10, 11, 13, 14, 16, 17, 18mm, SAE 9/32, 5/16, 11/32, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 23/32in