Metal lamp unit needing assembly (8)

I believe the answer is:

platinum

I'm a little stuck... Click here to teach me more about this clue!

'metal' is the definition.
(I know that platinum is a metal)

'lamp unit needing assembly' is the wordplay.
'lamp unit' anagrams to 'PLATINUM'.
However, I am not sure how the anagram is indicated.

Can you help me to learn more?

(Other definitions for platinum that I've seen before include "Precious metal, Pt" , "Heavy white metal" , "1 down, symbol Pt" , "Valuable substance" , "Valuable silvery metal" .)

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