US oil barrels
A US oil barrel, also known as a petroleum barrel, is a volume unit used in the oil and gas industry to measure crude oil or liquid petroleum gas (LPG). One US oil barrel is 42 US gallons or about 159 liters.
US federal barrels
A Federal US Barrel is 31 gallons which is about 117.35 liters. This unit is normally used for apples, potatoes and other agricultural products.