I've looked around and here is a choice, in various price ranges. The MM refers simply to the width of the ring, as distinct from the size (to fit your finger). If you decide to buy, make sure when you get to the Amazon website that you select the right size (there's a drop-down menu for you to do this).
The 8MM Men's Tungsten Carbide Ring with Celtic Design is highly polished, and features a raised matte finish center.
The 8MM Tungsten Ring with Laser Etched Celtic Design is another beauty with a simple but elegant interlacing.
A third one is the 8MM Tungsten Ring Wedding Band with Laser Etched Celtic Design.
Finally, if you'd prefer something plainer, here are two simple and elegant rings:
You can't go wrong with a tungsten wedding band. It will look as good as new after a long time wearing it, and it looks good on men. What is more, you can wear it in the gym or when you're doing rough work.