The equipment that is used to measure very small quantity of mass is called laboratory balances. These balances are capable of measuring mass even up to sub-milligram level. These balances find their application especially in the laboratory hence they are commonly called laboratory balances. The measuring pan of the laboratory is very light. The pan is covered with protective cover to avoid collection of dust in the pan which may affect the measurement. The covering used in such pans is known as draft shield.