This is a new in the package Piston Ring set (1 set for each piston..so this is enough rings to do all 4 pistons) for all years and models:  1979 1980 1981 1982  CB650 Four Cylinder.    This is a standard size (STD) ring set.  #13011-426-004.  This has the 2 compression rings and the 3 pc  lower oil control rings for all 4  pistons,  everything to get your pistons/ engine running nicely again with proper compression.  These are for stock Standard STD. bore size 59.80mm.  Get your old bike up and running again. We only sell the best!  This is a top-quality aftermarket item shipped new in the package. Good stuff if you are riding or restoring your CB650.  That is it!  If you may have a later 1983-1985 CB650 these model years take a different ring set size..we do stock that on our website too.. if you may need. If you may need new gasket set or clutch, we have those helpful items too.