OEM Husqvarna tune up kit which includes the air filter, fuel filter and spark plug. The part number for the air filter is 537143101. The part number for the fuel filter is 591375401. The spark plug is an NGK BPMR7A This kit will fit the Husqvarna trimmer models 326C, 326E, 326ES, 326HD60X, 326HD75X, 326HDA55, 326HE3, 326HE4, 326HS75, 326HS99, 326L, 326LDX, 326LS, 326LX, 326P4, 326P5, 326P5X, 326RJX, 326RX, 326SX, 327LDX, 327LX, 327PT5S, 327RDX, 327RJX, 327LDX.