This is the ValueSet that contains all the codes in US Surface Codes Set Value Set (http://hl7.org/fhir/us/carin-bb/ValueSet/C4BBSurfaceCodes) and US Surface Codes Set Value Set (http://hl7.org/fhir/us/carin-bb/ValueSet/C4BBSurfaceCodes). E.g. what you have to deal with if you get resources containing codes in either of them