UK gills
UK gills are volume measurements for liquids in the United Kingdom. One UK gill is equivalent to a quarter of a UK pint (about 142 milliliters).
Cubic Millimeters
A cubic millimeter is the volume of a cube 1 millimeter on each side, so 1,000 of them make a cubic centimeter. It is the same as a microliter, and a drop of water is roughly 50 cubic millimeters.