I got one of the Harbor Freight air rivet pullers a few years back. It had a bad o-ring and leaked oil right out of the box. Once that was fixed up it worked for a handful of rivets until the head jammed up on it. I spent more time fixing the thing than using it. I still have it hanging on the wall, but truth be told I usually just hand pull the rivets, or if possible use solid rivets instead of pulling out the HF pile of junk I got. I'm sure one from ATS or just about anywhere else would have been a better investment. At a Sonex Aircraft workshop they said they had great luck with them (the HF ones) so perhaps I was just the lucky sucker to get the one made out of all the reject parts..