Does it work on presta valves? 100 psi max should be good for most, but going over 100 psi isn't uncommon on road bikes. Looks like it displays in four different units rather than has four ranges. I imagine the actual pressure range is the same indendent of units displayed.

With presta valves on road bikes, I've never tried a separate gauge that I could get to work reliably without letting out a significant amount of air.