I saw a similar tool at tire shops but never thought to check what was in stock until I got new tires for my Walker mower. It's always a good idea to swap out the bars when changing tires as this is a common leak point. This tool is long enough to pull out old stems and install new ones. I used to cut the backs off the old ones, but this handy little guy lets you thread them straight through the hole. As mentioned, the retainer isn't the strongest, but mine didn't break on the first use. The barrel puller also worked well.