These 20-Liter polypropylene carboys are ideal for use in storing and dispensing solutions and media. Ideal for sterile water storage and can be autoclaved before refilling to stop recurring algae or bacterial growth. Excellent chemical resistance. Closure size is 83B (83 mm). Graduated to deliver in 1-gallon and 5-liter increments. Spigot boss molded in one piece with carboy, for strength and leak resistance. Spigot closure included. Sold individually or 4/Case. Nalgene#: 2319-0050.