A coat (but not a topcoat) for resale, possibly (6)

I believe the answer is:

sealer

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'a coat but not a topcoat' is the definition.
I can't judge whether this definition defines the answer.

'resale possibly' is the wordplay.
'possibly' indicates an anagram.
'resale' is an anagram of 'SEALER'.

'for' acts as a link.

Can you help me to learn more?

(Another definition for sealer that I've seen is " Arctic hunter; substance giving protective coat".)

I've seen this clue in the Evening Standard.

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