1. using liquid silicone for food, food grade, nontoxic, odorless, safe.
2. bottle of large diameter, poured into a convenient.
3. Hukou controls white cover of water flow can remove themselves, you can put ice and other bulky objects.
4. made of high-quality silicone, mildew and contains no BPA, certified by the FDA.
5. soft folded, stacked volume can store to any backpack pocket.
6. spherical shape, then fold leaving creases.
7. aluminum rounded loop for hanging.
8. containing 250 degree boiling water, cold-cold cryogenic temperatures.
9. stable, does not release harmful chemicals.
10. super light weight, space-saving, easy to carry.
11. when it is big enough, small enough when not, can stretch to pack heat freezing.
12. the seal is good, no leaks.