I haven't had to use the unit in the field yet, but when I received it I naturally used it to pump up a tire with both a CO2 cartridge and with the hand pump. Obviously pumping up by hand with such a tiny pump is not fun, but it does the job for those situations when you run out of CO2. It is straightforward to use and feels well made, though as mentioned, I've only tried once in the comfort of my garage.
