I just used it to add 2-3 pounds in both right side tires that were low. it's took about 1 minute to go from 30 to 32 pounds on my 20's but that is much better then going to a gas station or busting out my big ass compressor.
the one problem I had at first was the Switch that goes between Leak fixing and just plain air seems messed up, took forever the switch it over cuz it seemed jammed.
I might go exchange it since that didn't seem right.