A rubber spanner! (6)
I believe the answer is:
bridge
This might be a double definition.
'a rubber' is the first definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'spanner' is the second definition.
(I've seen this before)
Can you help me to learn more?
(Other definitions for bridge that I've seen before include "Structure spanning a divide" , "Span, connecting structure" , "Crossing point" , "Structure carrying a road, railway etc." , "Viaduct" .)