Hello this is the PAC RP4 VW-11 CAN-bus adapter with radio harness needed in specific Volkswagen models for an aftermarket radio. I had it in my 2003 VW Passat but I got a new car and don't have a need for this anymore.it is in like new condition works perfectly fine. This adapter is pretty expensive brand new so I thought I could help someone out selling a cheaper used one. Any questions feel free to ask