Need replacement
Thanks for posting. I am afraid we don't have an exact match for this casement operator. I believe our closest is the 3-171. Review the dimensions below and let me know if this matches what you have, or if any differs in what way.
Even if the dimensions match, the 39-171 has an 'offset' or bend you can see in the link arm that your operator does not possess. You have a few options to deal with this. First, you could try installing the operator as is and seeing if it works just fine; it might depending on the exact setup. If it doesn't, you could swap the link arms on both operators by drilling them out and then connecting the old link arm to the new mechanism with a rivet like our 62-014B. Just note modified items cannot be returned for refunds. Take a look and let us know if yo have any questions.