The patented Impactor process is another system that combines the HDD with pipe bursting as shown in the figure below. The bursting head (Impactor) receives air through the HDD stems. The HDD is connected to the air supply and positioned to drill out to an entry manhole. Then the HDD stem is pushed through old pipe to the next manhole and drilled back to the entry manhole. The Impactor device, after it is attached to the drill stem and to the replacement pipe, is pulled into the old pipe. While pulling back, the Impactor system is activated and bursts the old pipe. The combined actions of pulling using the HDD rig and of hammering by the Impactor breaks up the old pipe and replaces it with the new pipe. The Impactor system can reduce excavation and overcomes blocked old pipes.