I-31-1 Auburn Igniter (Spark Plug) Auburn I-31-1 Igniter (CS 12990) Replaces Eclipse 16927, Maxon 23739, Crown CA506, Champion F-121508, USI P-5022, I.C.E. 562767 Hex: 13/16" Thread: 14mm x 1.25mm Insertion Length: 1.87"