This is an ultra-light backpack, which is made of the durable Ultra-Sil Cordura nylon and with PU coating, which makes it waterproof to 2,000 mm. water column pressure. In addition, the backpack has reinforced shoulder straps, which prevent clumping during heavy loads. The backpack also has a built-in double zipper, which gives the user easy access to the bag. The bag has an integrated storage bag so you can reduce the backpack to pocket size. Super easy to take on the trip.