Ridiculously light, and durable enough for any trail, our 21 ounce Standard Mouth Lightweight Trail Series bottle is 25% lighter than our other 21 ounce bottles and provides the best cold hydration experience for your longest adventures. The narrow Standard Mouth opening is ideal for quick sips on the trail, and the slim bottle profile stashes easily into a pack pocket. Engineered to deliver lasting cold refreshment with TempShield insulation in an innovative lightweight stainless steel design.