This is a new in the package Piston Rings set (1 set of rings for all 4  pistons..enough to complete 1 engine!) for the 1977 1978 1979 GS750 models. This is a standard size (STD) ring set which is correct replacement for  65mm Standard bore pistons. Correct replacement for #12140-45013.    Each of the 4 rings sets has the 2 compression rings and the lower 3pc oil control rings for the pistons, everything to get your pistons/ engine running nicely again.   These were used on the 8 Valve models. These will not fit your engine if it is the later 16 valve engine as used on the 1980 and later models. We do have the rings on our website if you have a later year model bike ..just search and you will see the other style. 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 or  racing these cool bikes.