The SFC Soft Flask is a direct response to mountain athletes who want access to hydration carried close to the body, but without the bulk of traditional bottles or the volume of large bladders. Their flexible construction allows them to mold to the position in which they are being carried and they compress as they are emptied to take up less space in the pack. The special bite valve ensures quick and easy access to the contents. Use the 150 ml/5 oz SFC for gels (hint: many gels are water soluble so they can be diluted to make them easier to squeeze and swallow on the fly). The 500 ml/16 oz SFC delivers a good amount of hydration without being cumbersome in size or weight. The SFC is constructed from Thermoplastic Polyurethane (TPU) that is tasteless and completely free of PVC and BPA so they meet or exceed US FDA and EC regulations. If you are looking for a better way to keep up on hydration and gels in the mountains, the new SFC is the way to go!