There is a difference! RAM Premium Replacement Clutch sets feature OEM components used by the vehicle manufacturer when your car was built. You get the parts that belong in the car, not some low quality or imported replacement imitation. RAM Premium Replacement sets offer the best level of driveability and durability for your vehicle. Premium Replacement sets are not intended for performance or competition use. 10.5 x 1 1/8-26 spline. Diaphragm. 6 spring helix hub. Includes pressure plate, clutch disc, release bearing, alignment tool. OEM replacement kit. Not intended for competition. Clutches, Flywheels and release bearings are STRICTLY FACTORY WARRANTY ONLY. Customer must return the unit to RAM for evaluation and inspection. For a full list of warranty information please see our warranty information here