Self-storage rental (4)
I believe the answer is:
unit
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">self-storage rental</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for unit that I've seen before include "Kitchen element?" , "Subdivision of a whole" , "Single item; one" , "Whole - group" , "Operational team" .)