V-trimmed ground electrode promotes sharper spark focus Maintains stable operating temperature under all engine loads Champion Iridium - Maximum Performance. Premium Spark Plug Iridium center electrode delivers maximum life Fine-wire center electrode and V-trimmed for greater ignitability Heat-Active alloy allows electrodes to reach optimal temperature quickly Champion Iridium - the ultimate element. This spark plug's fine-wire iridium center and platinum ground electrodes provide the sharpest spark focus for maximum performance. MARINE