This is a A-21A810 Spark Plug PN: 21A810Main Description As Following : A-21A810 Spark Plug P.N: 21A810 7/16" ReachFor 4 cylinder gas tractors 1950-64 using unleaded fuel.Quantity: 4Thread: 14mm Stocked As: A-H12 Found in Section & Models : Ignition & Electrical Parts > Ignition & Related Parts, Ford / New Holland (UNDEFINED): SEVERAL Associated Items : New Also A-FO-O-16-46COMB, A-FO-P-FERGIMP, A-FO-S-CONSUMPR And : 7/16" Reach Quantity: 4 Thread: 14mm