This set contains 5 different elements - Copper, Silicon, Iron, Zinc and Tin. Each glass vial contains approximately 20g of each element. The glass vials are 30mL in size with black plastic caps. The entire set is held by a 1/8" clear acrylic holder with rubber feet. Included are 5 element cards describing the elements. They are business card size and laminated 5 mil. The purity of each element is greater than 99%. These are real elements not imitation. This is a beautiful set which will last a long time if properly cared for. This product was designed, engineered and manufactured by teachers for teachers in the United States by Mercury Manufacturing of Texas. A teacher owned company.