King WillDuo 8mm Brown Brushed Tungsten Carbide Wedding Band Ring Thin Rose Gold Groove Comfort Fit

How true to size are these rings? I wear something like an 8.75 so would an 8.5 or a 9 be better for me?

Does this ring contain cobalt or nickel? Will this ring turn my husbands finger green or irritate his skin at all? My husband has very sensitive skin.

Will the black fade at all or tarnish over time

is this ring real