Features SPECIFICATION: 1/4in drive has M4 M5 M6, 3/8in drive has M8 M9 M10 M12 M14, 1/2in drive has M16 M18. A total of 10 pcs bit sockets for you to use. CRV MATERIAL: These spline bit sockets are made from chromium vanadium steel, with high strength, ensures excellent durability. POLISHED SURFACE: The drill bit socket is corrosion prevention, with a smoothly polished mirror surface without burrs. STORAGE BOX: This triple square spline bit socket set comes with a tight and sturdy casing for easy carrying and storage. ENGRAVED SIZE: The spline bit socket has laser engraved size, which are clear to read, convenient for you to identify. Specification: Item Type: Triple Square Spline Bit Socket Material: Chromium Vanadium Steel Specification: 1/4in Drive: M4 M5 M6 3/8in Drive: M8 M9 M10 M12 M14 1/2in Drive: M16 M18 Package List:10 x Triple Square Spline Bit Socket1 x Storage Box Package List 10 x Triple Square Spline Bit Socket 1 x Storage Box