They are made of high quality zinc alloy, each coin comes with a transparent and stronger plastic shell; The coins can be collected for precious memories; They are great gift idea for friends, and will bring them good luck and blessings; With its unique style and charming astrological design, constellation coins bring us good luck and blessings; Material: Zinc alloy, Diameter: 1.58 inch(4 cm), Thickness:0.13 inch(3.3mm), Color: Silver.