You are bidding on a used Engine Computer/ECU removed from a 1997 Mercedes Benz S500 COUPE with AUTOMATIC TRANSMISSION.  The Bosch ID Number is 0 261 204 323 and the Mercedes Part Number is A 021 545 21 32  . Please make sure that if you bid on this ECU the unit that you are replacing has  the same ID number or is the otherwise compatible. Carefully examine the hi res pic which shows this item in considerable detail, do your own due diligence and make sure that it is suitable for your needs. To the best of my knowledge this ECU will only fit 1996 and 1997 S500s Coupes or Sedans.  This ECU was removed from an automobile with a blown engine but with only 155000 miles on the odometer. This Unit is Guaranteed to work to your satisfaction. You must be completely satisfied or your purchase price will be refunded. Shipping, packaging, and handling charges are non refundable under any circumstances.   Replace your defective ECU with this Unit right now or simply keep it as a spare. Eventually yours will fail as indicated by a no start condition and if you are stuck and need to purchase an ECU from your friendly Mercedes dealer it will set you back over a Grand .