Mahle OE plasma-moly top compression ring set in 4.030" diameter by .0625" thickness with .190" RW specification. The description specifies a steel top compression ring finished with plasma moly for applications needing that exact sizing and surface treatment. It’s supplied for piston rebuild projects that require OE-style ring geometry and wear-resistant top rings.
Mahle Rings Performance Plasma Moly Steel Top Compression Ring 4.030 x .0625 .190 RW Moly Ring Set