The award-winning and patented GoToob is made from soft yet rugged silicone, so it's easy to squeeze, and it dispenses the product right away. A special, "no-drip" valve helps the cap stay clean.The collar is made of two rings that unsnap from one another. The outer ring has an ID window, and the inner ring lists content indicators. Simply snap the outer ring off and back on to display "Soap," "Lotion," and more. A blank setting lets you write in your own content indicator.The GoToob is made of high-purity, FDA food-safe silicone. Silicone is one of the safest and most inert materials in common commercial use (heck, baby bottle nipples are made from the stuff!). It's not cheap material, but we decided to use silicone for the fantastic performance and safety it affords. However, no material is completely impervious. While GoToobs work great with thousands of different fluids, sometimes a fluid can react, affecting the silicone of the tube, altering the fluid, or both. This is due to reactivity with silicone itself and isn't limited to the specific silicone we use for GoToobs. Also remember that GoToobs are travel products, not long-term storage containers. Some products may change state (dry out or become less viscous) if kept in GoToobs for months at a time. It is a good idea when using any product in a GoToob for the first time either to test a small amount overnight or to pack the GoToob in a leak-proof bag for protection. We will happily replace your GoToob with a new one if there are any issues, but we can't say the same for whatever else you packed in your suitcase!