How are units used?

Units exist so the system can automatically convert items or other objects to the correct measurement when necessary. Items provide a good example for why conversions—and also units—are needed. Let's say you stock an item in units of ea (i.e., each). This is your inventory unit of measure. However, you might sell the item in a different unit. Let's say you sell it by the cs (i.e., case). Because the system sees different units for the item, it will automatically convert the ea to cs when the item is sold.