Made of spring steel and stainless steel.Internal tooth lock washers have teeth along the inside diameter. They prevent nut and bolt heads from loosening.
Internal teeth dig into the screw head while the smooth outside edge won't snag objects. These washers provide greater vibration resistance than split lock washers. Use with fasteners that have small heads, such as fillister and cheese head screws.
316 stainless steel washers have excellent resistance to chemicals and salt water. They may be mildly magnetic.
18-8 stainless steel washers have good chemical resistance and may be mildly magnetic.
400 series stainless steel washers have excellent wear resistance, but aren’t as corrosion resistant as other stainless steel washers. They may be mildly magnetic.
Zinc-plated steel washers are corrosion resistant in wet environments.