This is the threaded plate that an SPD-style cleat attaches to. It’s inside the shoe. We sell it because sometimes the threads holding the cleat get stripped -- it can be an overzealous tightening job or rust or both. Think it never happens? Guess again. Two top-ranked racers at the 2006 US National Cyclocross Championships had their cleats rip out of their shoes mid-race. Of course, they weren’t riding Sidi.