The Yellow Jacket Solenoid Valve Service Magnet is the quickest and easiest way to manually operate solenoid valves. It works by magnetically lifting the stem assembly and plunger to actuate the valve during service. Use this solenoid service magnet to test, troubleshoot, or manually activate and control a direct connected or pilot operated 2-way solenoid, 3-way reclaim or 4-way reversing valve typically found in a reverse cycle air conditioner or heat pump. This magnet can also be used to hold a solenoid valve open during recovery and evacuation so the entire system can be accessed.