The .585†Lift COMP Cams Beehive Valve Spring Kits for GM 6.6L Duramax Diesel Engines include everything needed to upgrade from stock springs: Beehive Valve Springs, steel retainers, spring seats and valve seals. Beehive Valve Springs feature a reduced diameter at the top of the spring to allow the use of a smaller and lighter retainer, reducing overall valve train weight. The lighter valve train combined with the stronger spring allows the engine to rev higher without concerns of valve float while an increased spring rate maintains valve train stability at elevated RPM to allow the use of more aggressive camshafts. The unique ovate Beehive shape not only has higher load but is more dynamically stable than the factory spring, ensuring valve train stability at elevated RPM and boost pressures.