An Irish article company promoted, unusual instrument (7)
I believe the answer is:
ocarina
'unusual instrument' is the definition.
'ocarina' can be an answer for 'instrument' (ocarina is a kind of instrument). I'm not certain of the 'unusual' bit.
'an irish article company promoted' is the wordplay.
'irish' becomes 'ir' (abbreviation).
'article' becomes 'a' (indefinite article).
'company' becomes 'co' (abbreviation).
'promoted' shows that the letters should be reversed in order (going up, in a down clue).
'an'+'ir'+'a'+'co'='aniraco'
'aniraco' in reverse letter order is 'OCARINA'.
Can you help me to learn more?
(Other definitions for ocarina that I've seen before include "Egg-shaped type of flute" , "source of music" , "Old wind instrument" , "Egg-shaped wind instrument with finger holes" , "we blow it" .)