Marketing device (3-2)
I believe the answer is:
tie-in
'marketing device' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tie-in that I've seen before include "Something linked to another item or event" , "Book, etc, linked to film, TV show" , "Relationship" , "Make a link (with)" , "Item linked with popular film, programme etc" .)