The "Quality Units of Measure" page is designed to store the Units of Measure Quality checks will be processed in. 

In the below example, I have stored Codes such as 'Degrees Celcius" or 'Units', but you are welcome here to add in any that suit your purpose. Simply create a unique Code along with a Description. You can also add the International Standard Code for the Unit of Measure but this is not mandatory.

Once these are populated, they can be chosen on your "Quality Check Codes".