Here we have a great item! This is 2 new sets ( enough for 1 engine) of Standards STD. size piston rings for the  now vintage Kawasaki KZ400 and Z 400 Models made in 1978 1979 1980 1981 1982. These are  correct and will fit the following models: 1978 KZ400 Z400 B1, C1 Special, 1979 KZ400 Z400 B2, C1, G1 (Customs) and H KZ400 LTD, 1980 KZ400 B3, G2 1981 KZ400 B4, G3, H3 (LTd). This will not work for the 1978 A model..those are a different type, but we do have that available on our website in a different listing.  This has the 2 compression rings for both pistons and the lower oil control rings.  That is it! Get your motor up and running! This is a top quality aftermarket ring set and is correct replacement for discontinued Kawasaki part # 13008-5019