Truefit Engineering Co. Ltd. Offers Carbon Steel Strip Locking Washers. Truefit Engineering Co. Ltd. Has been awarded ISO 9001:2000 certifications. Carbon Steel Strip Locking Washers are used with smaller nuts up to shaft diameter 260 mm. Carbon Steel Strip Locking Washers are supplied with a hexagonal head screw and spring Washer. For larger nut, these locking clips of design MS are used. The diameter of the shaft of this locking washer is 10-280mm. These locking washers are made of carbon steel strip material.