Watches, for a while, bits of it (10)
I believe the answer is:
timepieces
'watches' is the definition.
(I've seen this in another clue)
'while bits of it' is the wordplay.
I cannot really see how this works, but
'while' could be 'time' (I've seen this before) and 'time' is found in the answer.
'bits' could be 'pieces' ('piece' can be a synonym of 'bit') and 'pieces' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'for a' is the link.
Can you help me to learn more?
(Another definition for timepieces that I've seen is " Watches, for example".)