Feels too light to be solid metal. My guess is foil-covered plastic (evidenced by the texture on the back of the button). The flips are solid and metal. I'm not expecting them to last longer than a year or so, but even then well worth the price. While inserted they look like $10 links, and imho they look better than in the pictures. Grab a few for travelling, if they break or get lost, who cares?