[M8]

■ Shape: Toothed Washer, External Tooth.
The round washer has uneven teeth like gears on the outside and a slightly twisting and standing shape with overlapping teeth that say "stacked teeth" to prevent gap.
Also known as "tooth washers" or "chrysanthemum washers" when tightening bolts and nuts, the "spring action" which makes the teeth twist flat, and the friction between the teeth is increased, but scratches etc. are noticeable.

■Material: Iron
"Iron" is "steel" and is an alloy of iron containing carbon.
Although it is commonly used in many circulations, it is cheap materials, but due to the downside of it is easy to rust, many surface treatments will reduce corrosion.

■Surface treatment: Trivalent white
It has the same corrosion resistance as "chromate" and has the same possibility of imitation self-healing.
Unlike hexavalent chrome, it is non-toxic and compliant with RoHS directive. So it is used as an alternative to unichromate/chromate.
Color is "Silver Color".

Product Features:
Unlike the outer tooth shape of a toothed washer (washer), the "overlapping teeth" is that the outer teeth overlap without gap.
Overlapping without gaps increases friction coefficients and increases loosening effect.