Gasket Ring for Attix 50 - fits in a groove on the bottom of the motor head assembly and makes a tight seal to the canister. This model should be change periodically to ensure a tight seal and optimum performance. If you own an Attix 30 and want to use the larger capacity Attix 50 canister, you'll need to purchase this gasket ring and remove the stock Attix 30 ring from the head assembly.