One method is to use a section of 1/2" tubing and wedge it into the inside of a 3-piece airlock (you have to remove the plastic bubbler piece.) Another more popular method is to use an orange carboy cap and attach a section of 1/2" tubing. We have used both methods, never had a problem with either, but would prefer the carboy cap because the tubing is easier to clean and the cap attaches to the carboy with a better grip creating a better seal. We do sell line brushes to clean lines with. Anyone who wants to use large quantities of fresh fruit in the primary will want to use a blow off tube to avoid clogging an airlock. You might even want to have a double blow off using 3/8" and 1/2" tubing on our carboy hoods.(We recommend adding fruit to a secondary fermenter to avoid this.)