Cover telephone inventor against clash of interests (4,3)
I believe the answer is:
bell jar
'cover telephone' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'inventor against clash of interests' is the wordplay.
I cannot really see how this works, but
'inventor' could be 'bell' (Alexander Graham Bell) and 'bell' is found within the answer.
'clash' could be 'jar' (synonyms) and 'jar' is found in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for bell jar that I've seen before include "Item of laboratory equipment" , "one in lab" , "Glass cover used in laboratory" , "lab cover" , "Glass cover to prevent laboratory gases escaping" .)