This handle flips down when not in use and has 3 internal ball bearings for extremely smooth rotation when in use. It is the standard handle on the Twin Turbo Vise Fast Action Handle, and can be used to upgrade older versions of this product that did not have the flip handle. It can also be used on an tool where a smooth flip handle is needed, the threads to mount it are 5/16"-18
The story behind the development of the flip handle can be seen here:
