to 500ml of water, you'll get a whopping 59 servings from the bottle. During a tough week when I was running the Marathon des sables in the Moroccan Sahara, I used it daily and didn't have any problems with cramping or dehydration. What I liked most

took this to the desert (on my recent Marathon des Sables challenge) to give it a real going over. Aside from the weight, it faired impeccably. I felt confident throwing it in the bag during the runs and when it came down to the snaps it was both easy

temperaturesSimon Ward, triathlete and coach"I did the Marathon des Sables and everyone was scared of the heat - the hottest day was over 60°C. But it was dry heat, so the sweat dried on the skin and cooled us down. It was probably better than running in 30°C