ZoneControlA(R) CR: Position sensitive damping with 3 compression zones and 2 rebound zones, controlled by 3 independent pistons: Compression (C): Provides superior bottom out control through a 2-stage, telescoping internal compression stop. This feature eliminates the need for an external hydraulic bump stop Rebound (R): Secondary rebound stop will dissipate spring energy and stabilize the suspension directly following a large compression event. The internal rebound stop will also eliminate harsh top-out events and the need for an external limit strap. Bottom line: This maximum performance from a bolt-on shock application. Period.