In favour of pipes and various manufactured items (8)
I believe the answer is:
products
'various manufactured items' is the definition.
(eg mass produced products)
'in favour of pipes' is the wordplay.
'in favour of' becomes 'pro' (being pro a particular cause).
'pipes' becomes 'ducts' (I've seen this in another clue).
'pro'+'ducts'='PRODUCTS'
'and' acts as a link.
(Other definitions for products that I've seen before include "Goods" , "Commodities offered for sale" , "Commodities, merchandise" .)