What is 1mm?

1 millimeter (mm) is a unit of length in the metric system. It is equal to 0.1 centimeters, or approximately 0.039 inches. It is commonly used to measure very small distances, such as the thickness of a piece of paper or the diameter of a small object. 1 millimeter is a very small unit of measurement, but it is still commonly used in many fields, including engineering, manufacturing, and science.