Copper is sheet is typically bought and sold by the pound. The thickness of the sheet is measured in ounces per square foot rather than "gauge" which describes the thickness of steel sheets. 16 ounce copper, therefore, weights 1 pound per square foot. Therefore a 3' x 10' sheet of 16 ounce copper would weigh 30 pounds. 20 ounce copper weighs 1.25 pounds per square foot and is therefore 25% thicker than 16 ounce copper. Our Copper Sheet and Coil is typically either alloy 110 or alloy 122. In either case, our copper sheets are 99.9% pure copper and is 100% recyclable. This means when one of our copper products reaches the end of its life span, some of the cost of that product can be recouped by selling it to a recycling center.