This adaptor ring comes standard on all pro-enabled Flair Classic and Signature models, and is used to ensure a proper fit in the portafilter base. Remove the ring to use the PRO Brew Head and insert to use the Standard Brew Head.  

 This accessory requires the PRO enabled Flair, which would be compatible with any Signature PRO or PRO 2, and Flair manufactured after June of 2019.