COMPRESSION ADJUSTABLE Compression adjuster is controller for the compress stage of the shock absorber and springs to move fast or slow. There are three types THREAD SPRING PRELOAD Thread Spring Preload or adjustable spring screw. By threading the cylindrical shock absorbers, user can turn the preload to fine tune the spring and tighten a provided bolt to fix the ring in its position REBOUND ADJUSTABLE Rebound Adjustable is to control the recovery of the shock absorber. Fast or slow depending on driver needs. It is designed to have a volume control knob needle shaft Free Bleed oil through hole and the knob. Rebound is designed to sense the adjusted time adjustment dial. LENGTH ADJUSTABLE Adjustable length. It helps increase the length of the shock absorber. The two types can be upgraded to 10 mm or adjustable lengths +/- 5 mm.