Rugged polypropylene carboys with a molded-in bung to accept the polypropylene spigot (included) that can be operated with one hand. The 83mm polypropylene buttress screw cap has a built in silicone gasket for positive seal. Large handles help with pouring. They have excellent chemical resistance and are ideal for storing sterile solutions or sterile water. Steam autoclavable 121°C. When autoclaving, do not engage cap threads.