Safety Shackle Used by Mountain Climbers
Puzzle 5 of Reach New Heights Pack
Question is: Safety Shackle Used by Mountain Climbers
and the answer is: CARABINER
Word Meaning:
CARABINER — A metal link with a gate that can open and close, generally used for clipping ropes to anchors or other objects or for slinging gear (equipment) on one's person.
Definitions from Wiktionary.