The Polar Bottle is an innovative, made in the USA (right in Boulder), high-quality bottle that keeps liquids cool for twice as long as other plastic bottles. It insulates better than any other bike bottle on the market as it uses a barrier of air to prevent heat transfer. It is made of BPA-free and Phthalate-free LDPE (Low-density polyethylene) plastic, which carries recycle number 4. Polar Bottles have been made from LDPE since their inception. Plus, the bottle has been enhanced to allow for much easier squeezing so even the gentlest of hands can easily drink even after miles and miles in the saddle.