Nalgene™ polycarbonate carboys have polypropylene screw closure and TPE gasket. Clearboys™ are tough, glass-clear and autoclavable. 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. Spigot closure (Cat. No. 7-6423-0010) included. Graduated to deliver in 1 gallon and 5L increments. Closure size is 83mm. NOTE: Dismount and disassemble spigot before autoclaving.