Black Diamond Distance 4 Hydration Vest Features: Dynex (Nylon 100D + PE 200D) Body Material Dynex Ripstop Yarn Tear Resistance BD Stitch-less Edge Taping Technology 4-way Lightweight Stretch Mesh Removable on the Fly Z-Pole Storage 4 Fit Sizes. Extra Small, Small, Medium, Large Dedicated Race Ready Back Pocket with Expandable Storage BD.Dry™ Protected Device Pocket with Expandable Storage Secure Pocket with Key Leash for Valuables, with Expandable Storage Dedicated Bladder Sleeve Dual Sternum Straps Dual Locking Zip Chest Pockets Dual Soft Flask Pockets with 2 x BD Branded HydraPak® 500ml SoftFlask™ 100% BPA & PVC Free Distance 4 Hydration Vest