The latest version of the S-Lab Advanced Skin pack, the Hydro 12 is form fitting, with new front hydration flasks that shrink as you drink, more versatility for carrying accessories, and lighter than ever. The long distance running choice of Julien Choirier for his victory at UTMF. DIMENSIONS: 43 x 22 x 18. Motion fit trail. Sensifit. Twin link. PVC, Phthalate, Bisphenol-a free. 4D front soft hydratation. Soft flasks included. Blaster valve. 4D pole holder. Soft trims. Apparel sizing. Reflective. Safety blanket included - delivered with the bag as a key element of your safety, increases pressure on the blader to improve waterflow. Whistle.