Marvin window cranks

Looks like the worm gear stripped out of the operator, which means you need a new one. The bad news is that I can't identify what you have from this photo since I only see the base. I'll need you to remove the complete operator assembly from the window so that I can match it up to something in our inventory.

I still can't see the whole operator in these photos, unfortunately. The arms are cut off out of frame, but they're essential.

You can start by looking at our 39-031 and 39-032. These may be what you have. Carefully compare our dimensions and pictures to yours to confirm.