The LI-23 is a prismatic panel with a 3/8 in. female conical circle centered inside a 3/8 in. prismatic square. The orientation of the circle/square combination is parallel to the edge of the material and runs in straight rows. This panel is one of the most efficient lenses offered. The truss shaped prism design prevents sagging, while the two prism shapes keep the light distribution uniform, giving you the definition you want. Available in sizes up to 4 x 4 ft. Note - the Amber panel is a UV-BWF panel designed for the printing industry to block ultra-violet and blue light waves.