MR-4359 is a magnetic strut for rear right of the 2013-2019 Cadillac XTS equipped with the GM Magneride. This magnetically controlled loaded strut from Arnott is a direct OE replacement. The monotube damper is filled with magnetorheological fluid which is a synthetic hydrocarbon oil containing iron particles that are easily magnetized. The damper includes an electromagnetic coil which, when turned on, causes the magnetized iron particles to act in a way that changes the effective viscosity (and stiffness) of the suspension. Arnott's new universal magnetic strut, which fits the rear right side, connects to the vehicle's ECU with no modifications. This product is pre-assembled for safety with a new steel coil spring, upper strut mount, bump stop, spring seat and isolator. WARNING: Cancer and Reproductive Harm. www.P65Warnings.ca.gov