Need replacement for single arm crank operator

I need help to identify what part I need to replace my single arm crank operator. It is a truth arm but i cannot see any part stamp on this piece. There are part numbers on the hinges. The window manufacturer is Windsor and what looks like the date on the window is 1998.  The crank length is 13-1/2" and the rollers are nylon.  Please let me know if you have any other questions or need any other information.  Thank you!