Solid Silicone bung that will fit a 3,5,6 or 6.5 gallon glass carboy or 500ml flask.
The silicone is very pliable, making for a great seal. They are also very easy to clean and sanitize. The top measures 1 1/2" wide and the bottom is 1 1/8" wide.
While the FE478 carboy stopper is a great, economical choice, you may also want to check out our premium, silicone carboy hood FE496 as well. Working as both a solid or a breathable bung (depending on how the plug is set), the FE496 is like getting two bungs in one!