In modern times, many different types of oil, chemicals, and other products are transported in steel drums. In the United States, these commonly have a capacity of and are referred to as such. They are called 210 litre or 200 kg drums outside the United States. In the United Kingdom and its former dependencies, a drum is used, even though all those countries now officially use the metric system and the drums are filled to 200 litres. Thus, the 42 US-gallon oil barrel is a unit of measure, and is no longer a physical container used to transport crude oil, as most petroleum is moved in pipelines or oil tankers. In the United States, the 42 US-gallon size of barrel as a unit of measure is largely confined to the oil industry, while different sizes of barrel are used in other industries. Nearly all other countries use the metric system.