What Our Gearhead(R) Experts Are Saying: "I've used the Polar Surge Ascent all summer-it keeps my water cold longer than any other bottle I've tried. The Surge cap is leak-free and super easy to clean, and the flow rate is high enough that I'm not sucking air on big climbs."Long climbs and exposed trails are no match for the Polar Surge Ascent 20oz Water Bottle. Designed for fast-paced efforts in warm conditions, this bottle combines high-flow performance with lasting insulation to keep us cool and hydrated from the first mile to the last. The Surge(TM) cap delivers a solid stream with a simple squeeze, then self-seals for clean, no-drip transport when we're hammering over rough terrain. With its Tri-Layer(TM) insulation and reflective heat shield, it keeps our drink cold for hours-no more sipping lukewarm water mid-ride. Easy to clean, comfortable to hold, and shaped to slide effortlessly into bike cages, the Polar Surge is our go-to bottle when the heat is on.