Check the listing for details. Twin Bubble Airlock with 6.5 Rubber Stopper (Set of 2). Condition: New. Listed at 6.50 USD. Twin Bubble Airlock with 6.5 Rubber Stopper (Set of 2) Introducing the Twin Bubble Airlock with #6.5 Rubber Stopper – a reliable combination engineered to safeguard your beer or wine during the fermentation process. The Twin Bubble or "S" shaped airlock is purpose-built to allow the release of fermentation gas while preventing unwanted air exposure to your beverage. Not only is it highly durable, but it is also designed for easy cleaning, ensuring a hassle-free maintenance routine. Simply remove the top, fill it to the specified line with a sanitizer solution, and your setup is complete. Each package includes two Twin Bubble/"S" shaped airlocks and two #6.5 rubber stoppers, providing you with a comprehensive solution for your brewing needs.