Working just like a roll-top dry bag; the fully welded seamless construction of this PVC and 600D nylon waterproof backpack means you can sit the backpack in a puddle all day long and the water will never soak through. This Class 3 waterproof backpack offers many great features padded shoulder straps; padded back; padded lumbar; adjustable sternum strap; adjustable waist belt; top carry handle; an outer elasticized bungee; outer zippered mesh pocket; outer elasticized mesh pocket; reflective stripes; and an internal pocket. The hanging internal pocket features a zipper closure. Now your keys and wallet don’t have to sink to the bottom of all your old dirty clothes. To secure the main compartment after you roll the top down 3 times. Then you have the option of buckling the ends together on top; buckling to the side buckles; and or securing the rolled top in place with the grey nylon Velcro strap closure on top.