Designed for mountain bikers, gravel grinders, and all weather roadies, the Breakaway Muck Insulated water bottle features a Muckguard™ cap cover that protects the Surge™ valve from whatever the trail dishes up. The high-flow Surge Cap provides a sip or blast of water and self-seals to eliminate spills and splatter, even on your bumpiest rides. Tri-Layer™ insulation and radiant heat reflective technology keep your liquids cool twice as long, so you can stay cool on long and dusty days in the saddle. thanks to the. Available in three sizes, including a new 12oz volume - which fits any frame size and/or full suspension bike with limited real estate for bottles.