At 16 L of total storage capacity, this UTMB-capable Race Vest features Nathan's patented stabilization system, meaning there's a place for everything and everything stays in place. Multiple zippered compartments and stretch mesh stash pockets for organization and increased capacity, adjustable compression pulls to cinch down excess when pack is below full capacity, 3-way Propulsion Harness???. Equipped with a 2 L bladder, two front pockets hold up to 22 oz. Tru-Flex bottles, front zip smart phone-compatible pocket, breathable wall mesh shoulder straps, trekking pole clips, perforated back panel for breathability, removable safety whistle. Wt: 14.1 oz. (w/bladder).