For this one, we see Akro Corkscrew without needing to think about size. Sometimes a little smaller size might be a clue with a WV Swirl. And if something is larger than 3/4" then that seriously limits who we might think of having made it. If a WV swirl is coming in near one inch, you can be pretty sure it's Alley. But Akro corks can also be one inch. As were a few other makers over the years. Vacor is well-known for making large swirls in the modern day.