The Jiffy Replacement Spark Plugs are for use with the Jiffy Ice Augers/Drills.
The models as well as the engines they are to be used with are listed below.
The #4002 model fits the Jiffy 2500 & 3500 series 2-stroke engines as well as the Tecumseh 2 HP engine.
The #4003 model fits the Tecumseh 3 HP engine.
The #4290 model fits the Jiffy PRO4 4-stroke engines.