| Description | 15 segment Vertical Prism Bar provides 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30 PD (Note: 30 PD is on the bar). 4447 xx Vertical Prism Bar. | 16 segment Horizontal Prism bar provides 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45 PD. 4446 xx Horizontal Prism Bar. |