This is a A-839071M1 Plug Heater PN: 839071M1Main Description As Following : A-839071M1 Plug Heater P.N: 839071M1 New 400 watt engine block frost plug heater has a .75" diameter plug. Stocked As: A-5B360 Found in Section & Models : Tractor Parts Associated Items : New Also This is An Aftermarket Product And : New 400 watt engine block frost plug heater has a .75" diameter plug.