Set of 2. Includes adapter and two shims. Helper springs prevent dismounting of springs from perch on coilover without changing spring rate. Unlike assist springs, helper springs are specifically designed to have a minimal effect on the spring rate of the main coilover spring. Helper springs allow the spring to stay on mounted on the coilover perch when the shock is under negative or zero load, also known as droop travel. It is ideal to run helper springs on setups where you cannot preload the main spring due to height issues or when experiencing springs coming loose from the coilover perch.