Individual 1.5 Inch / 38mm Blue Green Copper Red 4 Hole Stoneware Button
This glaze is called Blue Green Red Copper. Although I've never seen the red, the blue green is saturated and intense. It's very reactive, and so you can see the translucence where the glaze is thinner.
If you are particularly interested in a specific button, please say so in the order note. I think they are all fantastic, but I understand that certain projects have very particular requirements.