Our engineers created a rail and guide alignment system that did not permanently bind the engine/transmission to the frame. A High Performance Urethane Vibration Inhibitor was developed and inserted in the guide. The rail would fit in the urethane inhibitor with minimum clearance on both sides. Once the conditions were starting to develop that would result in the harmonic effects and lose of control; the rail would come into contact with the urethane inhibitor, maintaining engine/transmission alignment, and stop the conditions before the wobble could start. After the alignment action is complete; the rail would return to its normal resting position. Hence we have created the only vibration free design. Our engineers have succeeded and now you can purchase a totally made in America product that is easy to install at an affordable price of $159.95. 30 day money back satisfaction promise ? you have 30 days to try it. If you are not satisfied with the performance of Smooth Rider, send it back for a 100% REFUND.