This a copy of a Dinan 24 pin chip for an E28 535i/is. I no longer need it as I am about to get a 745i motor installed in my car. I used it with great results in my US spec 1988 535is. NOT ALL 535s can use this chip, as some have (I believe) 28 pin chips. If you are interested, please check your box first. Unlike some, I will refund you money if you are not satisfied. I have once already because the buyer did not check his box first. $100, including shipping within the US. I think I covered all the bases.