Did you know that most pet charms on the market today contain lead (a heavy metal) and/or nickel (an allergic substance)? Our Unity pet charms base contains neither, making them a healthy and beautiful alternative. Because they are free of these harmful substances, they also make beautiful matching pendants or keychains for humans - adults and kids alike. Each unique piece of artwork is commissioned exclusively for Doggles Unity pet charms. Size: 21mm diameter.