Super water resistant with a water pressure of about 7.6 psi (20,000 mm) that can withstand heavy rain (*not completely waterproof); Weighs only 26.9 oz (790 g) and is ultra-lightweight so it wont burden your body. Made of original nylon for strength at the same time. The bottom is made of 1000D oxford nylon, so you can easily place the bag on the ground. It can be increased up to 1.2 gal (5 L) of capacity, so it can be used for overnight tents and 3 days (Note: depending on the size of the tent or sleeping bag equipment) In addition, the area where it is grounded with your back to reduce stuffiness. Also, by attaching the PEAKHUNT bottle folder or pouch that comes with the PEAKHUNT for added convenience.