77 mm UNDERDRIVE ALTERNATOR PULLEY FOR BMW  M50 / M52 / M54 / S50 / S52 / S54 ENGINES 

LONGER SERPENTINE BELT  REQUIRED

BOSCH -TYPE REPLACES BMW PART NO. 12311432988 OR 12311703736 OR 12311726139 FOUND ON M43 /  M50 / M52 / S50 ENGINES (PULLEY HEIGHT 41MM)

VALEO -TYPE REPLACES BMW PART NO. 12311713945 OR 12311436636 OR 12311703735 OR 12311403026 FOUND ON M43 / M50 / M52 / M54 / S50 / S52 / S54  ENGINES (PULLEY HEIGHT 49MM)