These buttons are made of genuine buffalo horn blended with a polycarbonate for consistency of shape and for a rich gray color. Expertly crafted in Japan. Superb quality as used by premium men's suit manufacturers. Set of 10 buttons- 2 larger buttons (a bit over 3/4" diameter or 20mm) for front of suit and 8 (about 5/8" diameter or 15mm) for the sleeves.