The patented Fizz Infuser is the key component of the Drinkmate system. With slow and fast pressure release options, you can easily prevent over foaming- this is the reason you are able to carbonate more than just water in the Drinkmate. When adding CO2 to drinks that contain tannins and/or sugars, this creates a lot of foam. The pressure release functionality on the Drinkmate Fizz Infuser allows you to depressurize these drinks without creating a big mess. Rinse under warm water after each use to keep clean. Having an extra infuser is useful: when the main fizz infuser is in use, or being washed when you want to make different kinds of drinks faster in case your main fizz infuser gets lost or damaged This includes the Fizz Infuser Only. The bottle the fizz infuser is attached to in the photo is meant for display only, bottle is not included.