It is a pad on a strap that has hooks and prusik loops at each end. Use the prusik loops to attach it to your Evolution saddle bridge, with the pad around your back. By moving the prusik loops on the rope bridge, you can position the band higher or lower on your back wherever you want extra support above the waist. The straps are adjustable so you can set them to your ideal length for comfortable support.
IMPORTANT: The Back Band is an add-on to your saddle for comfort purposes only; it is not part of the safety system of the Aero Hunter Evolution and must never be used for fall protection.