Dakine Vertical Reservoir - 3L. The Dakine Hydrapak design of the Replacement Reservoir is engineered to be durable and easy use. The Shape-Loc center baffle adds some rigidity to the shape of the bladder which cuts down on shifting of water weight while youre in motion and makes for a more resilient design. While the wide mouth opening and plug-and-play connecters make it easy to fill drain and clean. And of course its BPA and PVC free.