Blue-gray colored buttons. These buttons have a beautiful, shell-like luster. They give a simple yet stylish impression. The back side is a dark navy color with glitter. These are four-hole buttons, making them easy to sew and allowing for secure fastening. Size: 15mm Quantity: 20 pieces These are new, 20 pieces from a bulk purchase for handmade projects. There is no material listed, but the product name mentions "shell-like," so I believe they are plastic, not shell. #HalloweenOnMercari