window crancks

Not sure what to recommend. You are not showing us the dimensions and what type of gearing and link arm on your operator. I have listed on this page some operators like yours with the upper hole at the bottom. Take a look at the operators listed to see if you can pick out one that matches yours. If not, send us some photos of the internal workings of your operator. Also show us the end of the link arm that is missing in these photos, so we can see how it attaches to the window linkage. Include sizes of the link arm.