Split Ring Lock Washers (also referred to as "Spring Lock Washers", or most simply "Lock Washers") are circular washers split at a certain point to create a helical shape. This shape applies force between the head of a bolt or screw and the installation surface. This force creates a resistance to rotation and prevents nuts, bolts and screws from vibrating loose.
High Collar Lock Washers have a higher profile (thickness) than a standard split ring lock washer, and are designed to fit under the head of a socket cap screw. Applicable standards are ASME B18.21.1, DIN 127B, and United States Military Standard NASM 35338 (formerly MS 35338 and AN-935). Lock Washers in this selection are made from through hardened Grade 8 Yellow Zinc.