Milliliter (mL)
The milliliter, written as mL, is a metric unit for volume. It is one-thousandth of a liter or one cubic centimeter. It was established as part of the metric system and is used worldwide in medicine, cooking, and science. Because it measures small amounts, it is ideal for both everyday and laboratory use. It is the same size as a cubic centimeter, so people in different fields can easily understand it. This makes the milliliter one of the most useful and common units of measurement in the liter.
Imperial Gallon (imp gal)
The imperial gallon, shown as imp gal, is a British unit equal to 4.54609 liters. It came from English wine and drink measures in the 1800s and became official in 1824. The imperial gallon was used throughout the British Empire and is still used in the UK and some other countries for fuel and beverages. The liter is now used almost everywhere, but the imperial gallon still exists because of custom and local use.