43mm Coin Safe $10 strike DF for 55 cents each and

X43.6mm Air Tite $10 strike DF for 65 cents each. Plus a discount of 5 cents each if I buy 50.

I have a few that someone gave me a couple years ago and they have a black rubber ring that makes the $10 strike fit nice and cozy. A $20 strike also fits in the same capsule without the black ring. Does the black ring make it an airtite? Is there a $20 size WITH a black ring? Or maybe the rubber ring isn't necessary at all.