This is a genuine Black and Decker replacement part, it is sold individually. The Snap-In Knob is installed in the 242302-00 Crank Handle, on the list of Wormates shown below. Its purpose is to rotate the crank vise to open or close the vise jaws.
This replacement grip is designed to fit securely into vise jaws, helping hold materials firmly in place during use. It allows for flexible positioning to accommodate different shapes and sizes, making it a practical addition for a variety of projects. Replacing a worn or missing grip helps maintain a stable, secure hold for improved control and performance.