Progressive 413 Shocks For Harley Sportster The 413 Series Shock is simple, durable and will be an improvement to your motorcycle's suspension performance for as long as you are riding it. Features: High-performance freon-charged gas cells Double-wall construction 6-stage dampening Heat-treated hard-chrome rods, long life seals and fade resistant oil Backed by a one-year limited warranty Special cam adjusters permit easy pre-load adjustment