90% Quarter Circle Shaped Solar Screens using 5/16" x 1" Framing : Quarter Circle Shaped Solar Screens are measured using three measurements, a width, a height and a center height. The center height measurement is taken from the corner to the center of the arch. This solar screen is made out of the 90% fabric, we recommend this 90% fabric for all windows that get 4 hours or more of sun. We recommend the 80% fabric for windows that get 4 hours or less of sun, generally those windows that do not face West. This screen is made out of the 5/16" x 1" wide framing. We recommend building all large Quarter Circle Shaped Solar Screens out of this framing. This size of framing for support and strength is ideal for half circle screens larger than 30" in width.