Its quality rubber no defects. Bought it because #6.5 bungs didn't fit in my 1Gallon carboy. Well my carboy is a non-standard size so this #6 is still a bit too large so I have to reinforce it but better! No complaints it works as a stopper...

This is a great rubber stopper.

Its quality rubber, no defects. Bought it because #6.5 bungs didn't fit in my 1Gallon carboy. Well my carboy is a non-standard size so this #6 is still a bit too large so I have to reinforce it, but better! No complaints, it works as a stopper...

They arrived with mold on them, but it washes off. They fit just fine in a typical 4-liter wine jug.

Corks my carboys or fermenters perfect, and fits the airlock nice and tight. Have been using them for a while no, and they show no signs or wear or melt, so I would say they are good quality material that should last you a long, long time.

These are a better alternative than the screw on plastic lids for the one gallon jugs. Fits well, but can easily come out when wet. Nothing a little plastic wrap won't fix.