Genuine Tungsten Carbide Metal Top Quality Craftmanship Cobalt Free Scratch Resistance Water Proof Product Detail: Material: Tungsten Carbide Inlaid: Grey Carbon Fiber Finish: Polished Shiny Plating: Black Plated Shape: Dome Band/Comfort Fit The picture shows the ring width is 8mm Rings Width:4MM 6MM 8MM 10MM(If you want a width that is not in the options, please contact customer service, we will reply within 12 hours.) Us Size:5/5.5/6/6.5/7/7.5/8/8.5/9/9.5/ 10/10.5/11/11.5/12/12.5/13/13.5/14/14.5/15 Note: the character of the inside ring is "Tungsten carbide", which is deleted as default. If you stick to have it engraved on "tungsten carbide" inside of ring, please tell me and email to us when you have ordered. Tungsten carbide is ranked second hardest next to diamond on the Mohs scale, diamond being a 10 followed by Tungsten carbide as 9. Tungsten material does not cause irritation on the skin. Due to the Hardness of Tungsten carbide, Tungsten rings may be laser engraved, but CANNOT be engraved by hand. They CANNOT be stretched. Men Women Black Tungsten Matching Ring Gray Carbon Fiber Inlay Couple Wedding Bands Mens Womens Rings Couple For 4MM 6MM 8MM 10MM