This tool simplifies magneto timing on TCM (Continental) series C85/C90/0200 engines. No protractor on the spinner required, or other complicated tooling. Simply place it over the prop nuts and sight down the casing split to set the timing. That's all there is to it. It's foolproof. Comes with instructions right on the tool for easy reference. 1 lbs (0.5Kg) shipping weight.