I was fortunate enough to win the Nathan lottery, which came in handy as I decided to take up trail running. Without knowing too much about hydration packs I found this Nathan model extremely user friendly, it comes with a 2L bladder there is more than enough water to keep you properly hydrated. Nathan HPL has duel pockets in the front to give you the option on one side to add 16oz flask which is great to carry electrolytes and the other stores food sources & valuables. A medium size pocket on the back large enough to hold a phone & wallet.
Maintenance and cleaning for hydration bladder is straight forward and simple. The pack is designed to spread the weight out so it’s not all resting on your shoulders. Nothing but praise for Nathan’s HPL 020 2L Men’s Bluestone and would highly recommend it. Happy Trails