Champion | part number: REL37B REL37B SPARK PLUG Refer to this application guide for exact engine model applicability. Thread Size: 14mm Reach: 1/2" Shielding Thread: 5/8"-24 Standard Electrode: Twin Electrode Plug Gap: .016"-.021" Engines: Franklin Gypsy Major Russian Engines MSRP: Now: $132.35 Add to Cart Champion | part number: REL37B REL37B SPARK PLUG MSRP: Now: $132.35 Add to Cart