Vintage casement window operators

A home owner from Los Angeles, CA says:
Attached are a couple of photos of one of our vintage casement window operators. We are going to need to replace these throughout the house as most of the operating shafts are worn down. What model could we replace these with?
User submitted photos of a window operator.
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Dave Sr. from SWISCO responded:
Looking at you photos is seems like you could have an older version of our 39-344 and 39-358. However I believe the 39-020 and 39-021 standard wood sill operators could also work for your window. Take a look and see what you think.
A distributor from Los Angeles says:
Thank you Dave: Yes. These look right. Is the more expensive one better? Would it be best to try one first before purchasing them all? If it doesn't fit can we exchange?

Thanks again
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Dave Sr. from SWISCO responded:
I wouldn't say one pair is necessarily better than the other, it's just a matter of preference. If you think buying a sample first will help then definitely give it a try. Check out our Return Policy for information on returning parts.
A quick learner from Los Angeles says:
Many thanks. Will do.
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