Of course it's a better device (4)
I believe the answer is:
tote
'a better device' 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 can't see?
'of course it's' is the wordplay.
'of course' becomes 'tot' (I can't explain this - if you can you should give a lot more credence to this answer).
'it' becomes 'e' ('e' can mean 'electronic' which is similar to 'IT').
'tot'+'e'='TOTE'
Can you help me to learn more?
(Other definitions for tote that I've seen before include "Drag; betting system" , "It takes bets for horse races" , "Carry or shoulder" , "Carry - betting system" , "record of stakeholders' investments" .)