The most common and most likely answer to this crossword clue is the 8 letter word TENDRILS
T
E
N
D
R
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L
S
Buddy explains!

The straight part
We know that "items a climber needs" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case items a climber needs = tendrils.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 TENDRILS mean?
TENDRILS noun- A thin, spirally coiling stem that attaches a plant to its support.
- A hair-like tentacle.