Set of 4 Genuine NGK BPR6EIX (6637) Iridium IX Performance Upgrade Spark Plugs – Heat Grade 6. NGK Part Number: BPR6EIX. Series: NGK Iridium IX Performance Range. NGK Iridium IX Core Features. The slim tip generates a steady, concentrated spark across all RPM ranges, maintaining consistent performance over long mileage without electrode erosion.
