Mahle OE plasma moly steel top rings in this bulk set are specified at 4.000" outer diameter with a 5/64" radial thickness and a .146" ring width, sold as a 48-piece pack for rebuilders and shops. The plasma moly surface is intended for top-ring applications where improved wear characteristics are required, provided in bulk quantities for multiple engine builds or production use.
Mahle Rings Perf Plasma Moly Steel Top Ring 4.000in x 5/64in .146in RW Ring Set (48 Qty Bulk Pack)