A self-braking belay device made by Petzl. A GriGri is ideal for sport climbing and working routes. It utilitizes a self-braking or auto-locking system so that if the rope comes under tension or a load such as if a climber falls, a cam inside the device pivots and locks the rope, stopping the fall. The GriGri can only be used on ropes that are between 10mm and 11mm in diameter. Similar devices are made by other manufacturers, including the Trango Cinch.