Cup Buttons - Metallic Aqua. The Cup Button bead has a smooth, concave shape and 2 holes. It is loved for its charm, versatility and practicality. This high-quality Czech glass button is perfect for adding a touch of class to any project and can be used in a variety of ways such as a focal point in a design or as a clasp. Measuring 14mm with a .8mm hole size, Cup Buttons are sold by PotomacBeads in a pack of 30.