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. Instinctive, quick, easy access to your poles while running. Can be used also to attach a helmet. Engineered for very easy use in 4 steps: 1- undo the top strap and insert the top of the pole. 2- rotate the pole around your back. 3- place the bottom pole in the bottom strap. 4- adjust the top strap to lock the pole