Pipes (5)
I believe the answer is:
tubes
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">pipes</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know this)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for tubes that I've seen before include "Hoses, pipes, lines etc" , "Long hollow conduits" , "Piping" , "Hollow cylindrical shapes" , "Long hollow cylinders" .)