It is a newly tested Mercedes Vacuum pump, this controls the central locking system, and all of the above! I ake credit card with paypal, bidpay, THIS IS GUARANTEED TO WORK! I bought it but I needed something else for my car, it wasnt this problem, please make sure it fits your vehicle, as there will be NO RETURNS.This will fit S class W220 bigger cars usually have this problem with the pump going out!! Call me 760-406-3113 SHIPPING is: $18.00, and the price I am asking is: $250.00 RETAIL AT $430.00 + tax at dealer!