2-way Propulsion Harness; vertically adjustable sternum strap 1.5 liter hydration bladder with filter-compatible screw-top closure and bite valve Dual front essential pocket; one carbo-gel holster, 1 zippered; Power Stretch Mesh back pocket for stowing jacket, gloves, and/or sleeves Lightweight, breathable wall mesh with soft perimeter binding; feels great against skin and won't damage technical apparel Weighs 11.2 ounces; one size fits all