This is the ValueSet that contains all the codes in Units Of Measure (http://hl7.org/fhir/us/pq-cmc-fda/ValueSet/pqcmc-units-of-measure) and Units Of Measure (http://hl7.org/fhir/us/pq-cmc-fda/ValueSet/pqcmc-units-of-measure). E.g. what you have to deal with if you get resources containing codes in either of them