Trying to find correct replacement parts for center-mounted jalousie window operator

We just moved into a house with a lovely sunroom complete with jalousie windows. However, it appears the handles/extenders were removed for the winter and we can't find them anywhere, and consequently can't get the windows open.

I suspect we need a handle and a crank extender, but am not 100% sure. I'm also not sure what size to purchase, and if the sizes of these types of things were standardized, or were brand-specific.

We can't find the name of the manufacturer anywhere. The gearbox just says "patent pending" and then has a marking that appears to say A (in a circle), and below it, the number 1 (included in photos).

Any insights would be appreciated!

Hi Casey-

Thanks for this!
This looks just like the operators that we have, and would be a viable replacement. However, our issue is that we don't have anything to put inside the operator to crank the windows open with.

Do you have anything that would fit inside this operator? For example, the crank extenders under your mobile home window products?