Why do you want to improve the most successful shock in the history of the company? Because were always striving to push the boundaries, making better products is what drives us each and every day. The RS-12 Gas Shock has won back to back USAC National Sprint Car Championships but we knew we could make it even better. The RS-17 is a revision of the RS-MTX gas shock for 2017. The RS-17 is available in smooth or threaded body configurations and has and updated deflective disc basevalve design.