casement window latch worn out

Thanks for writing in. Take a look at our 39-083 21-1/2" and 39-140 16-1/18" Dual Arm Cranks. Compare the 'wingspan' dimension listed in the pictures on each shop page with your old operator, and see if one matches what you need. If you have an operator with a wingspan in between the sizes of these two, you probably are better off going with the 39-140 instead. The window won't open as far but it should function fine.