Springs are made from super-clean, stress relieved chrome silicon wire Provide excellent durability and resistance to load loss when using aggressive camshaft profiles Includes unique 10? super keys and retainers Wider key angle ensures a stronger assembly vs. the OEM 7? keeper angle High-strength chromoly retainers 0.685" (EU: 1,740 cm) lift capable spring assembly Kit fits 5/16" (EU: 7,938 mm) valve stems 184 lb.@1.850" [EU: 83,46 kg @ 4,70 cm] 443 lb.@1.230" [EU: 200,94 kg @ 3,12 cm] 1.510" OD 0.745" ID [EU: 3,84 cm OD 1,89 cm ID] Made in the U.S.A.. SPRING KIT .685 84-04 BT