Carboys are large-volume plastic or glass containers that typically hold 20 to 60 liters (5 to 16 gallons) of liquid. Plastic carboys can be made from different materials that are impact and shatter resistant and generally lightweight. Examples include polypropylene (PP), high-density polyethylene (HDPE), polycarbonate (PC), and polyethylene terephthalate (PET). Polypropylene carboys can be autoclaved for sterilization and PET and glass carboys are non-porous. Carboys can include spigots or stopcocks to facilitate liquid transfer, and some have built-in carrying handles for convenient transport. They’re available in a variety of capacities, in rectangular and cylindrical shapes with horizontal or vertical orientations, and with wide or narrow openings. These openings allow for easy filling and are located on the top of each carboy.