This Hop Bong Sight Glass is perfect for homebrewers and small - scale commercial brewers. It can be used as a dry - hopping device on top of the fermenter to purge oxygen from hop additions with CO2, or as a sight glass below the fermenter to carbonate finished beer or rouse hops. It has a 2 - inch tri - clamp size and is made of Nylon 12. The hop pellet capacity is 150–180g (5.2–6.3 oz).