I had one that came with a timing cover gasket set. It came in a little bag with a tube of red locking compound. All I had to do was clean the mating surfaces of oil, apply the locking compound, slide the sleeve into place (no tools required) and let it set up. It has worked beautifully on my brother's 200 mustang.
Strangely, it didn't come with instructions, or even anything to identify what it was for.