Bosch Workshop Engine Air Filters are constructed with a high number of pleats for robust particle holding capacity 98% filtration efficiency in removing small particles from incoming air to guard against engine wear High velocity cellulose cured media provides minimum air resistance and ensures even pleat distance for optimum efficiency Polyurethane foam seal provides elasticity and sealing performance, while protecting against water and heat intrusion into the air intake system All features combined ensure only the cleanest air for strong engine protection, high-performance, and better fuel efficiency Compatible with select vehicles (Note: vehicle trim level/engine may affect fitment - verify specific vehicle fitment details with fit checker above): BMW: 1992-95,2001-05 320i, 2000 323Ci, 1998-00 323i, 1998-99 323is, 2001-06 325Ci, 1992-95,2001-05 325i Compatible with (continued): BMW: 1992-95 325is, 2001-05 325xi, 2000 328Ci, 1996-00 328i, 1996-99 328is, 2001-06 330Ci, 2001-05 330i, 2001-05 330xi, 2001-03 525i, 1997-00 528i, 2001-03 530i, 1994-99,2001-06 M3, 2004-06 X3, 1997-02 Z3, 2003-05 Z4