Cryptic crossword answer help please

[Cannothtinkofaname]

The Daily Mail Pitcherwit cryptic crossword:

"Taken from cub as 'Tin Lung'

The answer is scuba which I can see is an anagram of cub as, but where does Tin Lung come into it? Anyone know please?

Thanks.

Tin Lung is what the actual scuba diving equipment is...

A tin lung is a name for scuba

Taken from tells you to change cub as to scuba

A tin lung is an oxygen tank on the back of scuba divers.

Ahhh, makes sense now!

Thank you all.