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.
Cubic inches
Cubic inches are units of volume measurement used in the Imperial systems equal to the volume of a cube with sides that are each one inch in length. It is used in the United States for measuring small volumes, such as the displacement of an engine or the capacity of a container. One cubic inch is equivalent to approximately 16.387 cubic centimeters.