Serrated Lock Washers

Serrated lock washers increase the friction between the bolt head/nut and the mating surface. Serrated lock washers provide excellent resistance to loosening. They do this by gripping into the mating surfaces. Please note that these washers come in two different types - internal toothed and external toothed. Serrated lock washers are installed between the bolt head/nut and the mating surface. And when it comes to loosening resistance, the externally toothed washer does a better job than an internally toothed washer. But the internally toothed washer comes with greater locking abilities. It can also allow the washers to withstand extremely high stress and force.
The bolted joint is then tightened in the same way as an unsecured bolt. In both internal and External types, the teeth bite into the joint material and create a holding pressure that doesn't loosen even during continuous vibrations. In most cases, a combination of both the fasteners is used to secure smaller objects in place.
In CBH it is available in different materials stainless steel, carbon steel, and alloy steel.