Ribz RIBZ Front Pack , Alpine Green, XL, 40-50 w, 11 liter GRN-XL-1123 The RIBZ front pack is made of 210d water resistant ripstop nylon. The ribs pack weighs approx. 11 oz. The use of a front pack repositions a portion of your weight forward which reduces your overall shoulder stress and increases comfort, mobility, and balance All components are water resistant and have proven durability in the most extreme of conditions. With an average storage capacity between 500 and 700 cubic inches, you can comfortably relocate your desired weight in the front packs.