ORV only uses nitrogen charged gas shocks for all their kits. Though a little more money, the nitro gas shocks in combination with the ORV kits provide a better ride both on and off road. By using an ORV lift kit and matching gas shocks, you optimize the suspensions capabilities giving you a better ride both on and off road. Another advantage to Nitro cas shocks is their ability to prevent body rool. This is extremely important, as body roll will kick in the ESP sensors on later model Jeep, which will shut the vehicle down.