This set includes a horizontal prism bar and a vertical prism bar made from durable, lightweight acrylic. The horizontal prism bar provides 16 segments at 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, and 45 PD. The vertical prism bar has 15 segments that provide 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 25, and 30 PD. Both prism bars come in a protective case.