SOURCE WXP 3L / 100oz Storm Valve Hydration System SOURCE Tactical Hydration Kangaroo 1L Collapsible Canteen I have both of these. Rarely use the 1L, but thinking I might when going light. But I rarely go light on water when I am with a group or puppy. Lately, I have been taking a 40 ounce insulated bottle for puppy's iced water. And the Israeli 3L bladder for me. I don't take three liters though. But I like the size. I usually put about a liter of water, a whole bunch of ice, then squeeze the air out to let it go flat. It fits perfectly in the back sleeve of my Tarahumaru pack. What I like best is the drink valve. Notice I did not say bite valve. Pull the valve open and you can suck from it or use gravity an it works like a spigot. Puppy loves drinking from it in spigot mode. And big top opening makes filling up and cleaning up easy. My Kangaroo is an old one with the drinking port. But it can also use the hose attachment making hydration on the go easy. I still love my canteen and canteen cup. And may just take that. But if going long, I would add the Heavy Cover canteen and cup too. I guess I have been on hard hikes and ran out of water, so rather carry what I believe to be enough. Especially when it is hot. And it is pretty hot in Hawaii. So today, like most days, I carry about 70 ounces of water. And by the time we were done, we had just enough left to get our bandanas wet and ice cold to put on our faces and necks. Heaven.