New For 2018, Seal Line's most versatile, feature-laden packing system sack, the Blocker Compression Dry Sack, saves space on paddling and trail adventures, while the waterproof valve rapidly vents trapped air to ease compression. All this with fully waterproof construction ensures essential contents are protected, condensed, and organized. Versatile materials: Lightweight 70D polyurethane-coated nylon materials are a tougher, more resilient cousin to the ultralight Blocker Lite materials. More durable and versatile, these materials are great for all-around use with confident waterproof protection. Smarter compression: Unlike conventional systems that pull against seams, Seal Line's Continuous Compression system encircles the sack to minimize seam strain, maximizing durability for dependable protection. Purge Air™-equipped: Unique and waterproof Purge Air valve vents trapped air, helping the sack compress further after being sealed, and are both more durable and more reliably waterproof than waterproof/breathable fabric membranes. 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: Pack Tight™ packing system sacks feature flat-sided, rectangular shapes that nestle closely together, packing 20% more efficiently than rounded sacks for easy, space-saving organization. Weight: 3.5 oz. Measures 3.5 x 6.4 x 11.8". Volume: 305 cu. in./5L. PVC-Free: Yes. Closure: Roll-down. Material(s): 70D polyurethane-coated nylon. Spot clean. Imported. Sealline 5L Blocker Compression Dry Sack.