NBR (nitrile butadiene rubber). BMW 5 Series Petrol Estate RWD -- E39 528i 1996|1997|1998|1999|2000 2793cc 142KW 193HP M52 B28 (286S1);M52 B28 (286S2). BMW 5 Series Petrol Estate RWD -- E39 520i 1997|1998|1999|2000|2001 1990cc 110KW 150HP M52 B20 (206S3);M52 B20 (206S4).
