Chrome vanadium steel with mirror polish finish, preventing oil and dirt from adhering to the spanner, making for easier cleaning and preventing rust. 72-teeth ratcheting system which needs only 5° movement to operate ratchet. Thin wall design for greater access. Conform to ASME B107.6. Contents 3/8", 7/16", 1/2", 9/16", 5/8", 11/16" and 3/4".