Rustproof & Durable: Constructed from high-hardness CRV chrome-plated steel, the triple square socket set surfaces feature sandblasting and mirror polishing. This design resists breakage and corrosion, ensuring years of reliable use. 10-Piece Set: This 10-pieces triple square bit set includes M4, M5, M6 (1/4"), M8, M9, M10, M12, M14 (3/8"), and M16, M18 (1/2"), covering a broad range of secure fastener needs. Easy Insertion: The spline socket bit set features a chamfered edge design with rounded triangular contact points to expand the contact area, ensuring smooth insertion while minimizing fastener wear. Precision-fit dimensions allow for easy alignment and secure threading, making screw insertion or removal effortless. Drop-Resistant Case: Our spline tip bit socket set comes with a durable black PE storage case with dedicated slots for each bit socket. The secure-fit design ensures the bit sockets stay firmly in place during drops, preventing scattering, loss, or damage. Clearly Markings: The triple square sockets set features deeply engraved, wear-resistant lettering that won't fade or peel. The larger, bolder markings make it quick and effortless to identify the right size for the job.