I had a harbor freight 12 volt impact for a good while, and it worked great for doing things such as taking on and off trike rims/tires, it doesn't have quite the power the electric impact guns do, but it was fairly stout, it had some sort of a clutch that would spin a few seconds and then the nut down, spin up again etc. I did eventually break it, but I got my 30 bucks worth. It was awesome for things such as trikefest and riding trips, I could hook it to a booster pack and carry it around wherever.