A useful variation of the figure of eight. Mainly used as the top knot on a top roping system by groups. This is because there is less wear on the rope as there are two bits under strain. But there are other uses for it. For instance in a direct belay system. As there are two loops that can be loaded, one can be for the climber, and the other for the belayer. It is also slightly easier to undo than a normal figure of eight as it doesn't tighten up as much.