The most common and most likely answer to this crossword clue is the 8 letter word AQUALUNG
I've seen this crossword clue in The Daily Telegraph
A
Q
U
A
L
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G
More clues leading to the result AQUALUNG
Buddy explains!
The straight part
We know that "It’s for those who need fresh air in the main" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it’s for those who need fresh air in the main = aqualung.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does AQUALUNG mean?
AQUALUNG noun- (underwater diving) A piece of equipment consisting of an oxygen tank and breathing apparatus used by divers to allow them to breathe underwater at depth.
- To scuba dive.