The Deuter Ascender 13L hydration pack is ultra-lightweight, super comfortable and geared exactly for fast-paced trail runs. Wide, ergonomic vest-style shoulder straps with an elasticated compression system, two adjustable sternum straps, and soft material against the back create a garment-like fit that keeps the pack with you as you move. A stretch mesh inner pocket and side compression straps help eliminate load wobble no matter how challenging the terrain, while a holster pocket on the front of one shoulder strap makes it quick and easy to access collapsible trekking poles. And there is space for soft flasks and a GPS in the shoulder strap pockets. The body fabric is made from 100% recycled materials and is bluesign certified.