Part Numbers: 28493 (Left) + 28494 (Right). ???? Left = Febi 28493. ???? Right = Febi 28494. SLK / SLC (R171 / R172) – 200, 250, 300, 350, 250 CDI/d, 55 AMG. ????WHY CHOOSE FEBI BILSTEIN?. Each arm is suppliedcomplete with hydro-mount bush, pre-fitted ball joint, and bearing for an effortless, plug-and-play installation — restoring the car’s original precision, comfort, and handling.