Crossword Genius

Designed to come out of a jar in one piece (10)

Ross

I believe the answer is:

shockproof

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'designed to come out' is the definition.
I can't judge whether this defines the answer.

'a jar in one piece' is the wordplay.
'a jar' becomes 'shock' (I've seen this before).
'in one piece' becomes 'proof' (I can't explain this - if you can you should believe this answer much more).
'shock'+'proof'='SHOCKPROOF'

'of' is the link.

Can you help me to learn more?

(Other definitions for shockproof that I've seen before include "Unshakeable" , "Resistant to impact" .)

I've seen this clue in The Sunday Times and The Times.
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