Flexible stoppers and caps are the best solution for glass carboys, because glass carboys have irregular necks. Better-Bottle's PET O-ring rigid closure fits all sizes of Better-Bottle carboys and has none of the drawbacks of stoppers or caps. The closure is made of a special PET that can withstand continuous service at 100° C (212° F) and is hydrophobic and non-porous, so it does not stain or take up flavors and is easy to clean and sanitize.
The O-ring closure only comes with the closure and plug.
Better-Bottle PET closure OPTIONAL fittings include: 1/8" NPT threaded plugs, equipped with 90° and "T" hose barb adapters for 1/4" ID hose; Does not include a low-profile Dry Trap fermentation lock, but it is recommended.
