Ultimate Direction SJ 3.0 Ultra Hydration Vest The vest design and fit is naturally stable, eliminating bounce and pressure points, for optimal security, efficiency, and comfort Two front bottle holders plus reservoir accommodation in back provides plenty of hydration during those epic races, ultramarathons, or just a long, scenic run Cuben fiber boasts the highest strength-weight ratio of any fabric in the world, for durable toughness without the hindering burden Power mesh holds contents while eliminating fatiguing bounce Fluid quantity is visible, so you can easily gauge use and plan accordingly; bottles easily accessible in front