The 412s simple, durable design means they will be an improvement to your motorcycle's suspension performance for as long as you are riding it. The double-wall steel body construction with nitrogen charged, multi-staged velocity sensitive valve gives you smooth, consistent damping. A five position cam style preload adjuster lets you dial in your ride whether you're a light rider or heavy hitter. With multiple options like full show black covers or black springs in progressive rate and length 14.25 inch , there is sure to be a 412 that's right for you and your bike. Heavy duty progressive rate spring.