The specialized s works rib cage ii carbon is a fact compatible lightweight and super strong bottle cage weighing less than 20 grams this is one of the lightest cages on the market and you wont notice any difference once its mounted to your frame with the swat tool integration you are able to attach the swat multi tool sold separately to the bottom of the cage this frees up your jersey pockets and saddle bag for extra gels tubes or just comfortable empty pockets coming in two understate