In a serious rescue situation, it might be possible that you would have to lower an extreme weight down a rock face. For example, there is the possibility that you might have to lower two climbers, one cradling another one, or you might have to lower a climber and a litter. There are many ways to do this, but there is one really smooth technique.
The super-munter is a variation on the munter-hitch. It creates a tremendous amount of friction and doesn't have one of the main problems of the munter-hitch, it doesn't tangle the rope. Indeed, the action of the rope as it goes through the super-munter twists the rope and then twists it back.
Following is a short video on how to make a super-munter:
The super-munter creates a great deal of friction. I have never used this for a rescue, but occasionally I have lowered two climbers together with this who didn't feel comfortable rappelling. I've always found it to provide more than enough friction to deal with 400+ lbs of dead weight.
While it is unlikely that you will use this particular hitch very often, it is a valuable rescue tool to have in your back-pocket.
--Jason D. Martin