Exhaust Springs - 57 mm Stainless steel construction gives superior strength and appearance, Swivel hook design eliminates binding, extending spring life, Exhaust springs should be measured when they are off the vehicle. Wear eye protection when removing, The length measurement should be taken from inside of hook to opposite end inside of hook, For correct fit, an exhaust spring should not be extended more than 20% of its length, Made in the U.S.A.