Searching for cr laurence H4083

Thanks for posting! Your casement operator looks a lot like the 39-091 ROTO Casement Operator. The opposite handed version is part 39-092. Although, are not able to supply you with a replacement for the arm, unfortunately. If it is still in working condition you will need to reuse it. Take a look at the dimensions below to confirm that these are the right fit.

Dimensions for 39-091

Your operator also appears to use the 39-557 Roto Spacer. The compatible crank handles are the 39-224 Fold-down Crank Handle and the 39-230 White Handle w/ Set Screw.