Our innovative hydration system- nearly every key component is patented or proprietary to Source. Our exclusive ""Glass-Like"" PE reservoir and tube liner naturally resists bacteria and eliminates plastic off-flavors. Dual opening system allows fast refills through the filler port, easy cleaning and ice insertion through the leakproof slider top. The patented Storm Valve provides much better flow than bite style valves and incorporates a handy shut-off in the valve itself.