Inspection chamber (7)
I believe the answer is:
manhole
'inspection chamber' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for manhole that I've seen before include "Aperture to sewer, duct etc" , "Opening with a cover giving access underground" , "Underground access point" , "Access chamber to sewer or drain" , "Drain cover" .)