This is a great find.   This is a new in the package Piston Ring set (1 set for each piston) for the  1978 1979 1980 1981 Honda CB400 and CM400 twin cylinder motorcycles. Some of these were called Hawks. This is a standard 70.5mm size (STD) ring set.  This has the 2 compression rings and the lower 3 pc oil control ring for both pistons, everything to get your pistons/ engine running nicely again.   Get your old bike up and running again. This is for both rings in the photo..so enough for 1 engine.  We only sell the best!  This is a top-quality aftermarket item shipped new in the package. Please consider the complete engine gasket set and engine Oil Seal kit we also stock if you are getting rings..as those may be helpful too.