This is the most often broken inner roller in the WWII Parker Appliance Company tube beading tool set. Our aerospace customers have requested that we design a high shear #4 inner roller for modern stainless steel tube applications. As such, we redesigned the roller with H11 tool steel and state of the art vacuum heat treating. This material is used on aircraft landing gear and missile parts. The #4 inner roller will fit all beading tools including Parker, ATS, and Graham Tool. This is a proven tool with a long history. Available to the public by popular demand. Manufactured in the USA. Useful to form a bead on rigid tubing for hose and hose clamp applications. Works on tubing from 1/4" O.D. to 5/16" O.D. Can be used on aluminum, copper, steel, and stainless steel.