From the Manufacturer
32 PSI Tire Pressure Valve Caps (set of 4) Take the pressure out of knowing when your tires are filled to their optimum levels. It�s a simple system. When tire pressure has reached its maximum normal level, our valve caps show green�a �go� for better fuel efficiency, increased tire longevity and smoother ride. When the green recedes, it�s time to get your tires checked. No more guessing. No more worrying. Screw-on caps replace existing valve caps in a snap; no tools required. Available in two pressure levels appropriate for most cars, pick-ups, vans, SUVs and CUVs.
