"Keep Downtime to a Minimum" with The Hero Preventative Maintenance Kit - John Deere X300 Series. This kit includes all recommended parts to complete a routine maintenance for John Deere X300 Series. All parts in this kit are designed and manufactured to meet specifications set by the original equipment manufacturer (OEM). This all-in-one kit includes: *This kit includes two different spark plugs to accommodate the specific requirements of each machine within a certain serial number range. To ensure you have the correct spark plug for your machine, kindly refer to your owner's manual (OM) and verify the appropriate part number. Please dispose of the spark plugs that are not needed for your machine.