HIGH-FLOW CAP WITH DIRT COVER: Designed for mountain and gravel bikers, the Muckguard protects the high-flow, self-sealing Surge valve from whatever the trail dishes up. Opens and closes with one hand, valve seals when closed. LIGHTWEIGHT CYCLING WATER BOTTLE: The original, 100% BPA-free bicycle water bottle. Minimalist single-wall design sheds grams and delivers maximum flexibility. DESIGNED FOR BIKE CAGES: Unique 15oz size was designed with mountain biking in mind - built to fit any frame size and/or full suspension bike with limited real estate for bottles. EASY TO SQUEEZE: Flexible, ultra-light materials and streamlined shape combine for a sure hold and high-flow squeeze. EASY TO CLEAN: The innovative Surge Cap is two pieces, cap and valve, simply twist and pull for complete access cleaning. Dishwasher safe. When we say easy, we mean it.