RENNtech Adjustable Suspension HSM Kit for CLS / E Class (C218 / W212)RENNtech Adjustable Suspension Digital Lowering Kit for 212 E Class and 218 CLS Class. Kit includes lowering springs for the front and the RENNtech HSM for the rear. As an upgraded option we offer our adjustable spring kit in combination with our RENNtech Hand Held Suspension Module (HSM) in place of the rear adjustable links. This allows the suspension system to remain balanced as the digital lowering module controls inputs to all four sensors on the