gas. Left.4 cylinder. Right.4 cylinder. A shock absorber is a device that controls the spring oscillations when the vehicle goes over various road irregularities, so the vehicle's tires remain in contact with the road. In some cases, shock absorbers have a secondary function as a suspension limiter to prevent the suspension from either over-extending and/or over-compressing. Cartridge and Base of the Suspension Strut Assembly. grommet. Suspension Absorber.