The SJ, SL, CF initials are API service ratings. They are one method of telling what a particular oil is good for.
I'm not a real fan of Advance Auto Parts, but they have a website that does a good job of explaining API service ratings.
HERE
This PDF is from Amsoil - another company that offers a pure synthetic oil. They also have some synthetic oils that are
specifically formulated for lawn and garden type equipment. I don't think Mobil does. (?)