11.02"" x 18.5"" x 4.92"". 27 liters or 1,220 cu. In capacity. Constructed of lightweight but rugged polyurethane coasted rip-stop nylon. Weights less than 1 lb. Top loading main compartment. Mesh airtech back system and padded shoulder straps. Four compression straps. One hydration port on right top. Multiple tool attachments.