Fully waterproof with minimal weight, our ultralight and uncomplicated BlockerLite Dry Sack boasts an efficient-packing shape to optimally organize and protect essential clothing and gear inside a pack. Ultralight: Featherweight 20D silicone- and polyurethane-coated nylon delivers waterproof protection while barely tipping the scales. Waterproof closure: Roll-top closure features a wrinkle-free stiffening strip to ensure a secure seal when closing the dry sack. Durable construction: Fully welded seams result in stronger and more durably protective construction compared to sewn-and-taped seams. Efficient-Packing: PackTight(TM) packing system sacks feature flat-sided, rectangular shapes that nestle closely together, packing 20% more efficiently than rounded sacks for easy, space-saving organization.