The reservoir bag is made by Source Vagabond Systems, and is called the Widepack, and it’s pretty trick. The Widepak closure is a variant of a river runner dry bag closure system, and is durable and leakproof. Just slide the top bar off the reservoir, fold open the bag, clean or fill as needed, then fold over and slide it back on. Source was founded in 1989 and manufactures in Haifa District in Israel, where they make hydration systems, adventure sandals and travel accessories. Besides the excellent opening system, the reservoir has the Z-Valve silicone mouth piece, Grunge-Guard (an anti-microbial treatment) and the Glass-Like surface (1000% smoother than other PU films) which prevents a bio-film build up. Which means no funk or slime buildup inside the reservoir, so water will remain fresh for a longer period of time.
The reservoir sits in a large pocket within the main compartment, so it’s not separated in another compartment like most brands. It certainly makes it easier to pull the bag out for filling and cleaning. Hanging off the back by the reservoir is a small coin bag, kind of a neat little zippered pouch for tiny items. The main compartment is nice and large, and the 2 zippers can be snapped together to prevent accidental opening. I must admit that I broke the snaps after a couple of weeks, so it really needs to be beefed up to be useful?
The front has 2 small pockets, the upper one being slightly larger with 2 elastic slots to hold tools and stuff, while the lower one would be for smaller items. There are also 2 side elastic mesh pouches, for sundry items. I do wish the main compartment had pockets, as this greatly helps in organizing gear.
The very bottom of the pack has a zippered compartment that holds a rain cover for the pack, which is a totally trick item! During rain storms, I get protected by wearing a jacket, but the poor pack gets drenched and water creeps slowly in and items get wet.
There is a detectable helmet net that clips onto the front of the bag, which should also be good for apparel items, etc. The loops for the helmet can be used to clip on elastic cords, and along with some very beefy red loops on the inner sides, and the top carrying strap, an assortment of attachment options can be used.