It's a Titanium-Carbide alloy I believe. I got it off amazon. Here's a link to the UK version if you want to look. I never take this one off, I have two but this is the only one I actually wear and unless I'm in the water or sleeping this ring stays on. I love it
https://www.amazon.co.uk/gp/product/B005HPQFM0/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1