Isky 9975 1.560" Dual Tool Room Valve Springs

The Precision 9900 Series "Gold Stripe" Tool Room Racing Value Springs by Isky. They're the world's only endurance test-certified racing valve springs, guaranteed "One of the Thousand", alumni of the grueling 1,000 mile Spintron endurance test, where two complete tests are run with a zero failure tolerance. No breakage and no excessive load loss are permitted, because it's pass or fail for Tool Room Springs. We test every batch of every part number we produce. We refer to them as The World's Finest Racing Valve Springs - because without a doubt whatsoever, they most certainly are!