The weight of a specified area of paper or paperboard is defined as the “basis weight”. There are a number of weights and areas used for specifying basis weight. Examples include pounds per 1,000 square feet (lb/1000ft2, sometimes referred to as lb/MSF) which is usually used for unbleached boards. Pounds per 3,000 square feet (lb/3000ft2, sometimes referred to as lb/3MSF), is the weight of a ream (500 sheets) of paper or paperboard of size 24 inches by 36 inches (2 feet x 3 feet). The metric measure of weight, “grammage”, is expressed as grams per square meter (g/m2), sometimes referred to as gsm). When the basis weight of a combined board product is reported, the weight is that of the entire product, including all components.