Foam Stopper 46-50mm
Breathable foam stoppers will withstand boiling or autoclaving temperatures, making them ideal for use in preparing a yeast starter. The honeycomb structure of the foam stoppers will act is a filter for any airborne bacteria or wild yeast that might enter the flask. That important because a lot of air is sucked into the flask while it is cooling. You can also leave the stoppers on the flask instead of a fermentation lock. Some people use foam stoppers to replace fermentation locks in their carboys, too.
The large foam stoppers are 46-50 mm wide and fit our 2000 ml borosilicate glass flasks.
They were packed so that they were kept clean and sanitary
This stopper is incredible. Almost perfectly cylindrical, dense enough to keep the yuckies out while staying delightfully squishy, if you’re making a yeast starter, this is the stopper for you.
It is foam and it does stop, so I must give it 5 stars...
Not much else to say, needed it for a flask, worked perfectly.
I found this will fit into most any flask from my 1l upto 3l.