The medium jack knife is a pattern where the blade or blades open from one end of the knife. This knife features two blades, the clip and pen blades. The clip blade is commonly used as a multi-purpose blade and preferred for detail work. The pen blade is great for small detailed uses, especially for everyday use such as opening envelops and boxes. This knife is constructed with CASE Tru-Sharp™ stainless steel which is a special high-carbon steel that helps the blades hold an edge longer than conventional steel. It also offers extraordinary blade strength and corrosion resistance.