Slime 4way Valve Core Tool & 4 Replacement Valve Cores

I have this tool already in my car's toolbox, but it will get replaced with this one. I ordered a 2nd kit to keep in my car's toolbox after I use up one kit. My tires are almost 5 years old, and one tire has a leak (about 8 PSI loss per month). No leaks were found in the tire itself. I had the bead seats on all 4 wheels polished, and seal goop applied to the tires, but the leak persists. The next step will be to replace all air valve cores. The valves depend on a rubber ring to seal, and rubber degrades over time. If that doesn't work, I'll have the valve stems replaced since the slow leak could be from the old rubber stem pushed into the wheel. Mag wheels get pitted, and can leak air through the wheel. While the tires are only 5 years old, the mag wheels are as old as the car (24 years). I may have to replace the wheels when I get new tires in another 5 years. This product provides a cheap troubleshooting step. All 4 cores will get replaced at the same time. I wanted a spare set to leave in the car's toolbox. I should've tried this before getting the wheel beads polished and sealant on the tire beads. This kit is just fine. The tool provides all the functions needed to replace the cores, and recondition the inside and outside threads on the valve stem end. Nothing complicated about this tool. For car tires, this tool is great. For bicycle tires, there could be a problem for clearance if the spokes at tight together. I won't know if the new cores eliminate the slow air leak until about a month has elapsed.