Cap assembly includes a seamless liner with premolded C-Flex fill and vent tubes to create an unobstructed fluid path. The 18" fill tube is plugged at the terminal end to maintain assembly sterility until use. Vent tube includes a 0.2-micron PTFE vent filter to prevent infiltration by contaminants. Vent filter is hydrophobic to guard against loss of costly product or media during filling or emptying. The one-piece liner eliminates the risk of bacterial entrapment and contamination and forms an elastomeric seal between cap and bottle rim. C-Flex tubing is manufactured according to cGMP and meets USP Class VI and USDA requirements. Tubing can withstand temperatures from ¿100 to 275¿F (¿73 to 135¿C). C-Flex tubing has exceptional tensile and tear strength, extremely low extractables, and excellent biocompatibility. The smooth inner surface reduces absorption and protein binding.