This is a A-386 Autolite Spark Plug PN: 386Main Description As Following : A-386 Autolite Spark Plug P.N: 386 1/2" ReachDim A (1): Autolite 386Quantity: 4Thread: 18mm Crosses To: A-AF415K BIG A , A-B1D16 AUTOLITE , A-B1SB386 ROTARY , A-B1SB389 ROTARY , A-LF3305 DELUXE , A-LF3305J DELUXE , Replaces: A-21A868 MISCELLANEOUS , Crossed From: D14 , Found in Section & Models : Ignition & Electrical Parts > Engine Related Parts, (Miscellaneous) (UNDEFINED): SEVERAL, Shop Supply > Spark Plugs, (Miscellaneous) (UNDEFINED): SEVERAL Associated Items : New Also This is An Aftermarket Product And : 1/2" Reach Dim A (1): Autolite 386 Quantity: 4 Thread: 18mm