My 2013 Honda Fit (and probably many other cars) was designed such that the tire valve stem does not extend far enough to employ a pressure gauge without removing the hub cap. I use a screw-on valve stem extender to get the valve stem out where I can access it, but first I have to remove the valve cap. I have been using long nosed pliers for that, but that's slow and frustrating.

This simple wrench has an internal taper which engages with the valve cap, so you can remove, install or tighten it. When you loosen the valve cap all the way to remove it, it stays inside the wrench so it doesn't fall down inside the hub cap. When you are ready to put the valve cap back on, you can easily get the threads started with the wrench, tighten it down and then pull off the wrench... all without getting your hands dirty.