The most common and most likely answer to this crossword clue is the 11 letter word BRIGANDINES
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The straight part
We know that "protective items" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case protective items = brigandines.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.
Crossword Answer definitions
BRIGANDINES noun- A coat of armor for the body, consisting of scales or plates, sometimes overlapping each other, generally of metal, and sewn to linen or other material.