Serpico Black Tungsten Commitment Rings for Couples 9mm.
The Metal that is used is a Nickel Binder that is higher in quality in comparison to cobalt. Cobalt is a inferior binding agent which may darken the color of the ring over time. Cobalt is most common in lower cost tungsten rings. This is due to the rings being mass produced in countries other than the United States.
Serpico grooved brushed black tungsten rings make excellent matching bands with the 8mm Serpico black dual grooved tungsten rings.