Inflatable air bladders for dynamic seat, drivers side, 2010-2016 Mercedes E class 2 door coupe and convertible. Provides adjustable lumbar support in dynamic seat option. This part is NOS in opened box. Since it has been sitting on my shelf for 5 years I bench tested it for a day and it properly held air pressure. Priced cheap to make room in my garage. IT IS YOUR RESPONSIBILITY TO RESEARCH THE PART NUMBER AND BE CERTAIN THIS IS CORRECT FOR YOUR CAR.