Type of printer seen over in hardware sale (5)
I believe the answer is:
laser
'type of printer' is the definition.
(I've seen this before)
'over in hardware sale' is the wordplay.
'over' shows that the letters should be reversed in order.
'in' indicates the answer is hidden within the clue.
'resal' can be found hidden inside 'hardware sale'.
'resal' in reverse letter order is 'LASER'.
'seen' is the link.
(Other definitions for laser that I've seen before include "Optical device producing an intense beam of light" , "Scientific apparatus" , "Device producing a narrow, intense beam of light" , "scientific instrument" , "Device producing an intense light beam - kind of sailing dinghy" .)