The Bennet Hook looks like a grappling hook that Batman would have on his belt, only it’s not for scaling buildings but climbing trees.
According to the company behind the Bennet Hook, Thompson Tree Tools LLC, it can provide a remote attachable secondary tie-in point (not for life support). The hook provides stability on long limb walks and gives access to large canopies without ever changing your primary tie-in. Also, with a practiced flip of the wrist, the hook can be retrieved.
Here’s an example of how it’s done:
One advantage the Bennet Hook offers is that it clinches to the limb when it’s under tension and won’t slide sideways. The hook works on limbs up to 12 inches in diameter and will cost you $360.