Ogio Hydration Reservoir Features Slide lock opening with large opening accommodates ice cubes and easy cleaning after use BPA-free polyurethane film is protected by Microban antimicrobial technology Hydration Reservoir utilizes radio frequency welded seam technology on seams and exit port to ensure a strong leak-proof bond Angled easy flow bite valve provides a constant flow-rate TPU tubing is odor free and taste free Volume markings on the front for making it easy to mix electrolytes or your favorite drink