The Mule Knot (a.k.a releasable knot) is ideal to lock off the rope on the belay plate. There are many occasions in climbing when, belaying from the harness using a device which does not self-arrest ...

It therefore offers the belayer optimal support and significantly improved safety. Mammut recommends use of the Smart HMS for the Smart 2.0. It is suitable for rope diameters from 8.7 to 10.5 mm.