Carrier type reflects the format of the storage medium and housing of a carrier in combination with the media type (which indicates the intermediation device required to view, play, run, etc., the content of a resource). Used as an alternative to or in addition to the coded expression of carrier type in field 007/01 (Specific material designation). Field 338 information enables indication of more specific carrier types and carrier types from various lists.
Multiple carrier types from the same source vocabulary or code list may be recorded in the same field in separate occurrences of subfield $a (Carrier type term) and subfield $b (Carrier type code). Terms from different source vocabularies are recorded in separate occurrences of the field.