382 Subfield $a - Medium of performance:

Subfield $a contains a term that indicates the instrumental, vocal, and/or other medium of performance.

Examples:

382  0#  $aclarinet$n1$apiano$n1$s2$2lcmpt

[A work for clarinet and piano.]

382  0#  $apiano$n1$s1$2lcmpt

[A work for solo piano.]