m fairly sure each is right at 10 gallons +. I made them that large so I could de-gas using a 5 gallon bucket. Made from a very large pipe with I think 1/4 plate welded it shut on bottom. Works great.  You can buy both chambers or just one. I will not ship. They are simply to large and heavy. Price is 400$ for the entire setup, and that is CHEAP! Located in Dallas Fort Worth area.