Independent testing has proven that corrugated extruded plastic is the best-performing in the industry, outperforming paper by 5 times (3-4 year life cycle vs. 3-4 uses for fiberboard). 2-year rated UV coating and produced using up to 90% recycled materials. Double faced, 160# weight extruded plastic sheets. 48 x 48 inches. Natural. 50 sheets per box.