The RRUNN Gel Flask is lightweight, easy to carry and has been designed to offer a sustainable & hassle-free solution for you to carry your favourite RRUNN Endurance Gels during training & racing. Each RRUNN Gel Flask comfortably holds 3 RRUNN Endurance Gel servings. Each flask comes with a hook so you can securely hook it to your shorts. For a half-marathon you can carry one flask with 3 servings, and for a full-marathon you can carry two flasks with a total of 6 servings. You may also use the flasks to carry water, or a hydration mix. By using this, you eliminate the need to carry sachets. This, in turn, cuts down on the plastic waste that is resultant of sachet use. Due to the design of the flask, we were unable to print a clear level marker for each serving, so you will need to understand this via usage.