The Mares XR Donut Wing is a tough wing for your twin set with plenty of lift & reliable function protected by a durable outer shell. Separate internal bladder is protected by an outer shell, inflated by a K-Valve with a central elbow that won't interfere with your 1st stages. Smooth Using the highest quality materials Mares have created a hydrodynamic wing that slips through the water easily with minimal drag. The internal bladder also allows for smooth gas shift for easy buoyancy control. Round bore inflator hose is 35" long connecting the K-Valve with metal buttons to the central 90° elbow. Specifications Lift: 24kg / 235N / 52lbs 1200D Ballistic Nylon outer shell Separate internal bladder 35" low profile LPI hose View product manual