Cold Tory detailed offensive poster's device (6,7)
I believe the answer is:
remote control
'device' is the definition.
(I have seen 'Electronic device' mean 'remote control' so perhaps 'device' could also mean 'remote control')
'cold tory detailed offensive poster's' is the wordplay.
'cold' becomes 'remote' (I've seen this before).
'tory' becomes 'con' (abbreviation for Conservative).
'detailed' means to remove the last letter (the word must be end-less or 'de-tailed').
'offensive poster' becomes 'troll' (I've seen this in another clue).
'troll' with its final letter taken off is 'trol'.
'remote'+'con'+'trol'='REMOTE CONTROL'
(Other definitions for remote control that I've seen before include "Channel-flipping device for a TV" , "Management from a distance" , "method of operating" , "TV zapper" , "Device encouraging sedentary habits in TV watchers?" .)