This is another of those tools that you rarely use, but when you do need it there really is no substitute. When fitting exhaust components they are very often a bit tight, especially when they've been on the bike a long time. Opening them up just that little bit to fit nicely is so difficult - but with this tool it's a breeze; just push it into the pipe and tighten it up with a spanner or socket. We've found ratchet spanners are the easiest method. This tool will work form 38mm upto 60mm, which covers most applications on bikes.