These springs offer bottoming resistance while retaining the supple ride quality on small bumps. They are available for all mono shocks found on; 05 RX-1, 06-15 Vector, 06-07 Rage, 06-07 Attak, and 06-15 Apex. We also offer springs for the Pro Action skid found in 03-04 RX-1, 05 Rage, and 04-05 RX Warrior. After placing order we will contact you to spec the proper spring.