Unit of measure is the way to measure your products and services quantities, it can be defined for movable goods or services, for example, Hours/Days for services, Kilo Gram and Grams for weighable goods, and pieces and dozen for packed products.
You can define whether this product or service measured by a decimal quantity or it is counted by a solid number, for example, if you purchased a product in Kilo Grams (1 Kilo Gram) and sell part of this product (1/4 Kilo Gram), so when you prepare your sales order or invoice you should type 0.250 Grams in the quantity field.
