CJ X-treme Duty Cylinder Assist Steering Gear Features a Large 3.125 piston (std is 2.75)diameter PSC now offers a 100% NEW Extreme Duty steering gear built to be as toughest steering gear on the market. This is not a remanufactured unit but a steering gears that is built with a combination of time proven new components that are superior for serious off-roading. Modified for Cylinder Assist All steering gears modified for cylinder assist applications are built to flow fluid throughout the circuits as efficiently as possible. There is actually a science to getting a cylinder assist system to work at its optimum performance. When it comes to cylinder assist steering gears, PSC builds one of the best you will find.