The Staun Products tire deflators come in a handy little leather pouch and can be screwed onto your valve stems at base camp and they will automatically deflate your tires while driving to the trail. The cool part is that they will stop at a preset pressure. Unfortunately, you will need to first lower a tire to your desired pressure by another method so that you can set the Staun units to stop at that pressure. We have found the Staun units very useful, but we also cut out the instructions and keep them with the deflators since they can be tricky if you don't use them often or want to change the pressure setting. However, if you know that you'll always air down to a certain pressure, simply set them to that amount and lock them in--then every time you hit the trail simply screw them on and drive. Remember to remove them before wheeling, and if they get dirty you should clean them as the dirt can influence their precision.