Lifetime Manufacturer's Precision wound Progressive Rate Some applications are offered in Heavy Duty and Standard Versions. Progressive Suspension Front Fork Spring Kit for Kawasaki ZG1000 1986-2006 / ZG1200 1987-2003 / Yamaha XV535 1990-2000 - Pair - Black - 11-1102 Progressive springs offer a soft initial spring rate for a progressively plush ride Wound design provides greater bottoming resistance as the spring compresses Improves handling while retaining OEM geometry Made in the USA