Casement window opener

Swico:

We live in a four unit condo. Each unit has a bay window with two casement side portions ? one left opening and one right opening. Several of them require several spins of the window crank before they start to move which, I'm guessing, indicates worn or stripped gear teeth. Based on the attached photos, can you identify the appropriate replacement openers before I go to the trouble of prying up the wooden trim pieces?

Thanks,

John