The Cassin Piu 2 belay device is designed to deliver optimal performance with the new generation of skinny ropes that have gained popularity in recent years. Using a variable notched design with smooth teeth on the brake side of the device along with narrower slots for the rope, the Piu 2 locks onto skinny ropes with more friction than other tube-style devices. Other features include the ability to set up the device in auto-block mode for belaying two seconds, a large rigging hole that allows a locking carabiner to rotate all the way through, a specially shaped hole that captures the nose of a keylock carabiner (specifically designed for use with the HMS Nitro and HMS Compact Lock carabiners) which can then be used as a lever for releasing tension if a second locks the device in auto-block mode, and a diagonal cable that prevents the rope from rubbing and jamming. Weight: 2.8oz. (80g). Rope Diameter: Minimum Double 8-9mm, Maximum Single 10-11mm.