Wicker slips have been a staple in oil tools for over 50 years. The main purpose of the slip is to lock the tool in place down hole, essentially very similar to how a brake pad works.
Once the tool has been lowered into position down hole, the tool is rotated pushing internal cones together which pushs the slip out and into the rock or casing.
The jaged teeth along the slip have been specially heat treated to much harder than typical steel at 58-62 HRC.
The increased hardness improves the durability and allows the slip to grip into harder rock or casing. While many slips are generic and can be used in a variety of oil tools some are specifically designed to work with a custom tool or toolset.