These powder coated, chrome appearing springs are made to fit with QA1's 4th Generation F-Body Pro Coil Systems. With a 2.125" upper I.D. and 2.5" lower I.D., these springs are offered in 3 rates with a 15" free length. Made with the highest quality materials, QA1 springs are strong, consistent and have a long life. All QA1 springs are lifetime guaranteed to remain within 5% of the original free height under normal operating conditions.