The Mountain Hardwear Fluid 18 Backpack was built for speed and stability in demanding environments. Its mix of lightweight, breathable comfort and locked down stability is perfect for applications like super tech terrain or distance trail runs. Tough, yet lightweight ripstop nylon fabric resists tears from snagged branches and jagged rocks. The hydration sleeve allows you to route the tube from over either shoulder or from the bottom of the pack depending on your preference. Close fitting suspension allows you to move without feeling your pack swinging around, and a stowable waist belt allows for additional support and security. Venting channels promote airflow to keep your back cool and dry. Finally, the Fluid 18 also has ample pockets to keep your smaller necessities organized, including integrated pockets on the shoulder straps, a stash pocket for easy access to snacks, and a fleece lined sunglasses pocket to prevent your shades from getting scratched.