NGK ZFR5F-11 - Normal Heat Range. If using Bosch spark plugs for this application, note that Bosch recommends using only #4419 (Platinum+4), 4312 (Platinum2), 4230 (Platinum), or 7526 (Super).
NGK ZFR6F-11 - Cold Heat Range for High-speed Driving If using Bosch spark plugs for this application, note that Bosch recommends using only #4419 (Platinum+4), 4312 (Platinum2), 4230 (Platinum), or 7526 (Super).
NGK ZFR6F-11 - Cold Heat Range for High-speed Driving If using Bosch spark plugs for this application, note that Bosch recommends using only #4419 (Platinum+4), 4312 (Platinum2), 4230 (Platinum), or 7526 (Super).