Optimum Control has many default conversions such as 16 ounces in a pound and 1000 ml in a liter, but there may be specific conversions for an item that you need to enter. For instance, from weight to volume or perhaps converting a number of ounces to a jar size etc. for this item.
Some examples of this would be spices. Bay leaves for example you may want to use by the leaf or by the gram, but perhaps you need a cup conversion for this. There are many internet sites that may have this conversion but you can also go to the kitchen and weigh a cup of bay leaves for use in your recipes.
To Enter a Unit of Measure conversion for an item