These tough, glass-clear polycarbonate autoclavable carboys are ideal for dispensing sterile water, aqueous reagents and media. Use in cold rooms, even at subfreezing temperatures. Spigot boss molded in one piece with bottle, for strength and leak resistance. Polypropylene Spigot and Screw Closure w/TPE gasket included. Graduated to deliver in 1-gallon and 5-liter increments. Closure size is 83B (83 mm). NOTE: Dismount and disassemble spigot before autoclaving.