The OPST Chuck Shank holds articulated shanks down to 0.9 mm (0.035 in.) in standard vise jaws while you tie, arrange and dress materials on the shank. It is an essential tool for making articulated flies. The tool will fit in any vise. Also fits tubes with diameter under 2 mm (0.08 in.), by unscrewing the chuck housing and flipping the inner chuck end-for-end.