Feature●🍺 REPLACEMENT PART - For BrewDemon brewers using an airlock with our 2 gallon system. Over time these gaskets can flatten out causing the airlock to no longer work properly. These replacement gaskets simply pop into the lid to maintain the airtight seal.●🍺 CREATE AN AIRTIGHT SEAL - This item is necessary to create the airtight seal required when using an airlock with BrewDemons 2 gallon conical fermenter.●🍺 Home brewing made easy - only with BrewDemon!Description For those BrewDemon brewers that use an air-lock. Over time these gaskets can flatten out and no longer keep an airtight seal. These replacement gaskets simply pop in and out of your black fermenter lid to help keep that seal airtight when you are using an air-lock or blow-off tube.