"Great tool to keep in your glove compartment," wrote a fan. "Even if your tires look like their pressure is OK, this tool will give you an accurate reading. With gas prices rising, well-inflated ...

The result was a quick-and-dirty mod that allows the calipers to be powered by a AAA battery. The average AAA cell has 5-10 times the capacity of the typical LR44 coin cells used in these devices.