Mahle OE HV385 top ring set, 4.095" diameter by 1.5mm (.151") with RW moly specification. The listing identifies a plasma-moly treated steel top ring variant (HV385 profile) sized to 4.095 inches and 1.5mm thickness for direct-fit applications. It’s intended for engine builders who require the HV385 ring profile and the precise 4.095 x 1.5mm sizing.
Mahle Rings Performance Plasma Moly Steel HV385 Top Ring 4.095in x 1.5MM .151in RW Moly Ring Set