Suitable for typical 20L bottles. The silicone plug can be boiled to disinfect and unlike cork/rubber will not crack or harbor infection. Also, it has a hole in the center that can accommodate an 8mm wide airlock, tubing and blowoff tubes.
its size is 50mm (middle) makes it ideal for bisleri bottles, carboys, demijohns and other similar vessels that need to be fitted with an airlock or pipe. If your hole size is smaller, we do have a size 5 rubber cork with a hole for this purpose.