Aftermarket 58mm head gasket seal for the shower screen/group head for your home espresso machine that uses the larger 58mm group head. This is the main seal between your portafilter and the espresso machine. It is a serviceable item and signs of wear usually display with water leakage from the group head when extracting an espresso shot. Fits Breville home dual boiler espresso machines with 58 mm group head such as BES900XL, BES920XL, BES980XL, BES990XL This WILL NOT FIT BREVILLE BARISTA EXPRESS, see our listing here for 54mm. Inner Diameter: 4.8cm Outer Diameter: 7.2cm Got the gear? Don’t forget the good stuff. Grab our bestselling espresso beans to go with it - add on the Espresso Starter Pack to try three different brews or the all-star Meebz Blend. Installation/Warranty We have sold hundreds of these seals. The correct installation method is important not to damage the seal and we do not accept liability for any seal damaged during installation. Although we offer a video tutorial on how to replace the seal we recommend the seal to be installed by an authorised espresso technician.