5/16" External Tooth Countersunk Lock Washer - .333/.318" I.D. - Steel - Zinc - Grade 2 - 100 Pk

External Tooth Lock Washers secure bolt heads or nuts to increase the bearing area and offer greater hardness so that the nut or bolt can be rotated without distortion of the bearing surface. Hardware is constructed of high quality steel for long lasting durability.

Internal Tooth Lock Washers lock into bolt head or nut to prevent backoff rotation, which works best with smaller head screws, such as fillister heads. Hardware is constructed of high quality steel for long lasting durability.

Combination Internal/External Tooth lock washers provide dual benefits. The internal teeth lock into bolt heads or nuts to prevent backoff rotation, which works best with smaller head screws, such as fillister heads. The external teeth secure bolt heads or nuts to increase the bearing area and offer greater hardness so that the nut or bolt can be rotated without distortion of the bearing surface.

External Tooth Lock Washers secure bolt heads or nuts to increase the bearing area and offer greater hardness so that the nut or bolt can be rotated without distortion of the bearing surface. Hardware is constructed of high quality steel for long lasting durability.

Internal Tooth Lock Washers lock into bolt head or nut to prevent backoff rotation, which works best with smaller head screws, such as fillister heads. Hardware is constructed of high quality steel for long lasting durability.