Box of novelties I supply (10)
I believe the answer is:
television
'box' is the definition.
(I've seen this before)
'novelties i supply' is the wordplay.
'supply' indicates anagramming the letters (supply of letters to make).
'novelties'+'i'='noveltiesi'
'noveltiesi' with letters rearranged gives 'TELEVISION'.
'of' acts as a link.
(Other definitions for television that I've seen before include "box set" , "Tube" , "Gogglebox" .)