Material:They are all made of stainless steel. it is lead free and nickel free,hypoallergenic, it doesn??t rust, change color or tarnish. Measurements: The big round pendant: Diameter is 20 mm(0.8), little heart pendant : 9 mm(0.35).Manual measuring permissible error. Perfect gift for mother. Three separate necklaces featuring sterling silver cut out heart disc for mother and tiny heart necklaces for daughters. Included in this listing are three necklaces (one large heart pendant and two tiny heart pendants); they could be for a mother and daughters or grandmother and granddaughters. Very sweet and would make a lovely gift! Perfect for any occasion! They will come beautifully packaged, and ready for gift giving.