In its annual report for 2009, Corning noted declines in sales for most of its products. But it also said that these declines were "offset somewhat by an increase in sales of Gorilla glass, a protective cover glass that is optimized for portable display devices. Sales of Gorilla glass have continued to increase as the Company moves to capitalize on market opportunities for this product." Why might sales of Gorilla glass be less affected by the business cycle than sales of some of the firm's other products, such as screen for LCD televisions or ceramics used in automobile emission systems?