They're snappy and may be a scream! (7)

I believe the answer is:

cameras

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

'they're snappy' is the definition.
The definition suggests an adverb but the answer is not.

'may be a scream' is the wordplay.
'may be' indicates an anagram.
'a'+'scream'='ascream'
'ascream' with letters rearranged gives 'CAMERAS'.

'and' is the link.

Can you help me to learn more?

(Other definitions for cameras that I've seen before include "Light-proof boxes" , "Image recorders" , "television equipment" .)

I've seen this clue in the Evening Standard.

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