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.
UK Barrels
A UK barrel is 36 imperial gallons (not to be confused with American gallons), about 163.659 liters or 0.163659 cubic meters. It is based on the traditional wine barrel used in the United Kingdom.