Agreement about securing current for musical instrument (9)
I believe the answer is:
accordion
'for musical instrument' is the definition.
(accordion is a kind of musical instrument)
'agreement about securing current' is the wordplay.
'agreement' becomes 'accord' (an accord is a formal agreement).
'about' says the letters should be written backwards.
'securing current' becomes 'noi' (I can't explain this - if you can you should believe this answer much more).
'noi' reversed gives 'ion'.
'accord'+'ion'='ACCORDION'
Can you help me to learn more?
(Other definitions for accordion that I've seen before include "Cad I croon about a musical instrument" , "Squeeze-box" , "box-shaped musical instrument like melodeon" , "Free-reed aerophone" , "Bellows-operated instrument" .)