BXT 4 Pockets 35 L Shoulder Foldable Nylon Backpack with Bottle Holders nylon Material: nylon(waterproof) Easy to folds up into small pocket. Large?capacity: 35L//Dimension:18.5X13X6.3inches(unfolded) Unfold at the airport to avoid excess baggage charges. Two large side mesh pockets for water bottles or umbrella.