Rubber stopper with airlock hole

Rubber bung with airlock hole. #10 Diameter of approximately 50mm across the top, tapering to a diameter of approximately 41mm at the bottom. Used with the Carboy – Plastic – 23L, Carboy – Plastic – 11.5L & FerMonster 23L PET Fermenter Airlocks available: Standard Airlock Senior Airlock