This is a tool used to prevent the flywheel from rotating during clutch replacement. I designed a part for an 06 BMW 325i with an N52 engine and a Getrag 6-speed clutch. I think this will work with most BMWs since they use the same number of splines on the flywheel. The tool is designed to be mounted on a pin at the 6 o'clock position and use one of the old aluminum bolts (or something similar) to hold the tool in place while tightening the flywheel bolts. The kit comes with a 0.15" spacer, which I ended up not using. This was done in case of problems with the dowel.