This durable backpack is uniquely designed with plastic stiffeners to effectively seal the roll top. Simply roll the top three times for a reliable seal in any conditions. MATERIALS: .55mm 500D PVC Tarpaulin. Puncture and tear resistant material that withstands elements and abrasion. Welded for a waterproof bond. BACKPACK STRAPS: Padded backpack straps with reinforced box stitching. Breathable back pad provide extra comfort. SPECIAL FEATURES: Tie down accessory loops along both sides of dry bag. OVERALL DIMENSIONS: 33.5" X 19" dia.