Closeouts. Polarpak's Flowjo hydration waistpack goes above and beyond just quenching your thirst. The MOFLOW (more flow) system, designed around an air pump, is made with antimicrobial film and Microban® hardware for protection against germs. Its unique design is proven to increase your water intake by 30% with every drink. As a bonus, the Flowjo adds lumbar support when inflated.