Grappling hook

The grappling hook was a tool used by Altaïr Ibn-La'Ahad in his search for the Chalice.

In 1190, Rafik gave Altaïr the grappling hook, allowing the Assassin to traverse gaps and chasms, as well as pull enemy guards towards him, allowing him to deal the final blow.

Reference

 * Assassin's Creed: Altaïr's Chronicles