Driven D Axis Swing Arms Spools are made using a unique 3 piece design for added style and allow the use of "race style" rear stands on most late model sport bikes. Using rear spools and a race stand allows for easier maintenance, allows the bike to take up less storage space, and gives you the ability to remove the rear wheel for tire changes. Driven D Axis spools are sold in pairs and use the threaded mount already on your bike's swing arm from the factory so no permanent modifications are required.