"Valve-Mate II" radio controls are pre-wired, tested, and easy to install. The Valve-Mate attaches directly on the spool of your existing hydraulic control valve and does not alter your hydraulic system. This system is operated by an air cylinder using your trucks compressed air. If your truck does not have air there is a pilot pressure compressor available to supply air for this system. They also offer a lifetime warranty on the radio and the air system. A pressure protection valve is required by the D.O.T. and is sold seperately. This unit is made special to run the SP8000 side puller. It has a special function that limits the use of the jack legs. You have to hold two buttons simultainiously to use either of the jack legs. This helps prevent the legs from accidentally being used during a recovery.