It breaks rocks - big chunks, literally smashes them into pieces!!! I usually use the BOSCH Chisel RTec Speed SDS-max 400mm with a pointed tip, for maximum impact performance. With a long chisel or bar, it will not give its maximum impact. It is good to wear a belt for continuous work, because it has some weight that strains the waist if used for a long time, especially in a bent position. It does not tire the hands in terms of vibrations. It has a good impact!