I started using the GU Flask for mountain bike races this past year, and it was a game changer. So much easier to pull that out of the jersey pocket, open with your mouth, get your gel, and put it back in the pocket. Eliminates the hassle of multiple packets in your jersey, trying to get the trash back in your pocket, and getting your jersey all sticky. My go to is the Sea Salt Roctane.

At first I thought this was kind of gimmicky. But with the cost of gels ($1.45/packet), I thought I would try it. I also disliked all the trash individual packets generated. And how many times have you seen empty (and full!) packets on the side of the road? Either dropped by accident, when trying to get something else out of your pockets, or on purpose. That doesn't happen with the flask. And no sticky messes. Fits into a jersey pocket and I can't even feel it. Holds plenty for majority of my rides (5-6 hours). In no time the flask will have paid for itself, since every serving I am saving 45 cents. Doesn't sound like a lot, but when you ride as much as I do, that will really add up!

I purchased one of these for a race this past weekend and was very happy with it. I have to be honest, I am not a fan of GU brand gel, but rather, used Hammer Gel in it. It worked like a charm. No mess, no garbage, and easily stowed in one of my hydration pack chest pockets. I have already recommended it to a few trail running friends.