Made of spring steel and stainless steel, serrated external tooth lock washers create a ratchet action, by biting into the nut or screw head and the surface it contacts. External teeth provide maximum holding power.
The teeth on these washers bite further into the screw head and joint than standard external-tooth washers to provide a stronger hold. Use with fasteners that have heads large enough to make contact with the teeth, such as pan, button, and binding head screws.
18-8 stainless steel washers have good chemical resistance and may be mildly magnetic.
Zinc-plated steel washers are corrosion resistant in wet environments.