Made of super strong and abrasion resistant 420 D nylon, with a panel of eVent fabric at the apex. Air squeezes out through the eVent panel as the bag is slid into the hull. Once stowed, air is drawn back into the bag which aids flotation. The TPU laminated fabric has a 10,000mm waterhead and is double stitched with tape sealed seams. Like all dry sacks, this bag is suitable to keep contents dry in any wet situation where the bag is not submerged.