This is a new in the package standard size (STD) Piston Ring Set  (this is a complete ring set for All 4 Pistons! so enough for 1 engine for all 1977 1978 1979 1980 1981 Kawasaki KZ1000 model motorcycles.   This is a standard size (STD)  70mm ring set.  This set of rings only fits the C models for 1981. All other 1981 models and later years take a different size ring set. This has the 2 compression rings and the lower 3pc oil control rings for all 4 pistons, everything to get your pistons/ engine running nicely again.   We only sell the best! This is a top-quality aftermarket item shipped new in the package.  Correct for part # 13008-5012.  Good stuff if you are riding or restoring or AHRMA racing one of these cool bikes. 

This is correct for these models from 1977-1981:

KZ1000 A1/A2/A3/A4

KZ1000 B1/B2/B3/B4

KZ1000  C1/C1A/C2/C3/C4

KZ1000 D1/ D3

KZ1000 E1/ E2