Key cylinder with thumbturn

A quick learner from USA says:
I am trying to NOT replace the whole thing but change the offset key cylinder with thumbturn ..just incase I have the parts by a ruler so you can have a clue on what part I need for my door . I see ya'll have different sizes and don't seem to match with the ones I got. I hope the images are helpful.

User submitted photos of storm door hardware.
Profile picture of Dave Sr.
Dave Sr. from SWISCO responded:
Let's see if I can help you with this. Take a good look at our 40-123 key cylinder. It appears to be the one you are looking for. Review its measurements and dimensions to see if it a match to yours.
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