From what I've read about it, it's main feature is that it supposedly has the same performance as a 110#-120# anvil. The reason being is that instead of distributing the weight throughout the horn and heel, it focuses all of it in the base footprint with a 2" radius on one side with a 3/4" hardy. Because of this Sawyer-esque shape and weight distribution, there is more weight under the hammer than a typical anvil (in theory).
-kniifechan