High lift high pressure spring kit. Reduces total valve train mass. Great for high performance & racing performance builds. The dual springs are manufactured from the highest quality clean chrome silicone wire, shot peened and heat treated for maximum fatigue life. Kit includes dual springs with internal damper to give a wider range of harmonic reduction, upper collars, lower collars, valve keys and seals. Max valve lift: .655". Installed height: 1.810". Seat pressure 185 lbs. Open pressure: 450 lbs. @ .655" valve lift.