AST 5100 Series Coilovers Lotus Elise S3 11+ | Non Inverted (ACA-L1203S) (SPF1203S)The 5100 Series shock absorbers for the 2011+ Lotus Elise (S3) utilize non inverted high performance monotube technology. In the past, these were known as the 4100 series. Monotube design shocks absorbers give your car a better performance than the standard twin tube design, the gas pressure is separated by a floating piston, and eliminates cavitation and airation within the oil chamber. The 5100 Series shocks allow rebound adjustment with one knob.