She's a gem producing listening device in Poland (5)
I believe the answer is:
pearl
'she's' is the definition.
'device in poland' is the wordplay.
'device' becomes 'ear' (I can't explain this - if you can you should give a lot more credence to this answer).
'in' indicates putting letters inside.
'poland' becomes 'pl' (e.g. on number plates).
'ear' placed into 'pl' is 'PEARL'.
'a gem producing listening' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for pearl that I've seen before include "coming out of shell?" , "prized example" , "Lustrous structure inside an oyster-shell" , "Off-white colour" , "Oyster's gem" .)