Features of the SealLine Blockerlite Dry Sack Pack Featherweight 20D silicone and polyurethane-coated nylon delivers water defense while bArely tipping the scales Fully welded seams result in stronger and more durably protective construction compAred to sewn-and-taped seams Packing system sacks feature flat-sided Rectangular shapes that nestle closely together Packing 20% more efficiently than rounded sacks for easy Space-saving organization Materials have a reduced environmental impact over vinylcoated materials Fully waterproof with minimal weight Ultralight BlockerLite Dry Sack boasts an efficient-packing shape to optimally organize Protect essential clothing and gear inside a pack Roll-top closure Features a wrinkle-free stiffening strip to ensure a secure seal when closing the dry sack.