The one problem with the tool you mention, which probably all of us DO own and HAVE used....if you use it after the center spool is out, then it is a COMMITTMENT! Once you insert it down and lock the pin, it ain't coming out! IF the cartridge is still stuck then so are you! I have come close to that situation! When the water is pretty hard, and the cartridge has been in place 10+ years, that baby is tight! SO, many folks prefer some of the other methods, of which there are many. The #6 easy out, and the tap, are among them.