With penetration breaking, you want to concentrate the energy on a smaller area, so the chisel tool is most commonly used for this process. It penetrates and removes a large piece of material. The tool is trying to split the material very similar to a hammer and a wood chisel, and can be generally used in trenching. The small surface of the tool transfers force to a small surface area of the material and breaks with a wedging action. Suitable for utility work and day-to-day breaking.