This is a A-21A873 Autolite Spark Plug PN: 21A873Main Description As Following : A-21A873 Autolite Spark Plug P.N: 21A873 Dim A (1): Autolite 216Quantity: 4Thread: 14mm Replaces: A-AL7C FORD , CONF12405A VAPORMATIC , A-C0NF12405A FORD , A-H10 RIVERSIDE TRACTOR , A-H10C MISCELLANEOUS , A-TY6070 JOHN DEERE , A-21A807 MISCELLANEOUS , A-216 MISCELLANEOUS , A-72068662 ALLIS CHALMERS , Crossed From: M4E4 MIGHTY , SM021F SPLIT-FIRE , WR9FC BOSCH , W7EC BOSCH , W9AC0 BOSCH , 1559450 GMC HOUSINGS , 1559452 GMC HOUSINGS , 1559483 GMC HOUSINGS , 215 AUTOLITE , A-216 , , 2677 AUTOLITE Found in Section & Models : Ignition & Electrical Parts > Engine Related Parts, Case-IH TRACTOR: SEVERAL, Shop Supply > Spark Plugs, (Miscellaneous) (UNDEFINED): SEVERAL Associated Items : New Also A-MNL18344 And : Dim A (1): Autolite 216 Quantity: 4 Thread: 14mm