Stapler used for wall covering (7)
I believe the answer is:
'wall covering' is the definition.
(I've seen this before)
'stapler used' is the wordplay.
'used' indicates an anagram.
'stapler' is an anagram of 'PLASTER'.
'for' acts as a link.
(Other definitions for plaster that I've seen before include "Substance for coating walls" , "One to cover wall, wound" , "Material applied to walls" , "Adhesive material" , "Cover for cut" .)