This X4S undercarriage track kit includes 4 tracks.Adapter kit required for mounting to your vehicle.Idler and mid-roller wheels:Increased width (26 mm) provides better track supportDouble bearing bolted on wheels for easier serviceabilityStandard and replaceable sealed bearings for economic maintenanceThe new Camso X4S is the next generation of track system that provides the ultimate versatility, stability and handling on any terrain all year-round.New geometry of solid steel frame provides better front steering and handing.