Since you are attempting to use this type of thing as fall arrest and not just body weight support, it's even more severe an application than what CountyComm has to say about this item:
IMPORTANT: The Micro Grappling hook is not designed for life support applications and should not be used for such applications. As with all tools, use with extreme caution. Special Note To Ninja Warriors: This will not support your body weight.
For the larger one:
# These Hooks Are NOT Certified For Life Support Activities And Should NOT Be Used For Any Life Support Function. They are designed to pull trip wires.
>Use It As A Specialized Grappling Hook To Remotely Capture Lines, Tear Down Phone Lines, Reposition Barbed Wire Emplacements, Disrupt Wires, Move Packages and Bags, Rake and Break Windows, Tear Down Blinds/Curtains in SWAT Entry Applications.
IMPORTANT: The pocket grappling hook is not designed for life support applications and should not be used for such applications. As with all tools, use with extreme caution. This was designed to snag trip wires in a combat enviroment, not snag shopping carts full of rocks from a creek or whaling operations. Use the appropriate tool for the task at hand.