https://permasteader.route66custom.com/cloud/index.php/s/yFjnDjwNWmmEXHy
Chart at top lists standard stopper diameter at the bottom of them.
Airlocks are cheap and you can buy the stopper/airlock as a pair. Don’t have to worry about propping up tubing to get a dip in it or finding the right size tubing to fit a hole in a stopper or trying to shove soft tubing through a hole in a rubber stopper etc. You can get three stopper/airlock sets for less than $10 on ebay/amazon. If you don’t like either of them you can do a web search for wine making supplies. Might even find a brick and mortar within driving distance.
I’ll be getting some more airlocks at some point just because they’re worry free. I’ve got 1 so I can buy 2 sets of 3 for less than $20 to cover my 7 jug method.
Yeah I found some on Walmart.com. Not going to mess with tubing , thanks.