The UL measurement is a symbol used by the International System of Units to represent a microliter. A microliter is a metric unit of measurement for liquid volume and is equal to 1/1,000,000 (one-millionth) of a liter.
The International System of Units (SI), also known as the metric system, is recognized by countries worldwide as the standard international system of measurement. SI measures liquid volume in liters and uses scales of measurement as multiples of ten. According to the SI system, "UL" represents a measurement of volume where the symbol "U" stands for "micro" (millionth) and "L" stands for "liter."