Graduated polypropylene carboys can be used for storing and dispensing solutions, media. Ideal for sterile water storage " 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 bottle, for strength and leak resistance. Polypropylene spigot and screw closure w/TPE gasket included. NOTE: Dismount and disassemble spigot before autoclaving.