Air-powered instruments (6)
I believe the answer is:
organs
'air-powered instruments' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for organs that I've seen before include "Groans over distinct parts of animal body" , "Periodicals published by special interest groups" , "Heart and lungs are vital ones" , "Large wind instruments with keyboards" , "Functional units in the body" .)