Screenshot coming soon.
The Assassin Gauntlet is the forearm bracer that carries the twins' Hidden Blade, rope launcher and dart gun. It is the reason you can zip up buildings and string ziplines between rooftops in Syndicate, and its tools unlock as the story goes on.
Fire it at a ledge to climb a tall building in seconds, or between rooftops to make a temporary zipline. London's wide streets and taller buildings are the reason Ubisoft added it.
Syndicate also has a range of gauntlet items you craft or unlock, from the Reinforced Gauntlet (£2,500, 100 Metal, schematic from On the Origin of Syrup) up to the Legendary Assassin Gauntlet (£10,000, 150 Leather, 100 Chemical and Bluestone, schematic from Level 5 Loyalty with Clara O'Dea). Downloadable packs add the Redback, Industrial and Royal gauntlets.