For optimal fit and top performance on fast runs in the terrain: With the Women's Aenergy TR 5 from Mammut, you always have your gear and equipment under control! The trail running backpack is designed as a lightweight vest construction, features a pleasantly breathable fabric on your back, and keeps your gear and equipment secure and chafe-free against your body even during intense runs. The wide shoulder straps are anatomically shaped and, together with the numerous adjustment options, ensure an optimal fit. The back compartment is easily accessible, and it includes a hydration system compartment, two holders for the included soft flasks, as well as quickly reachable pockets for energy bars, gels, and trekking pole holders. Great!.