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.
UK fluid ounces
A UK fluid ounce is about 28.41 milliliters, a little smaller than the US fluid ounce of about 29.57 milliliters. So 1 US fluid ounce is about 1.04 UK fluid ounces.