Our High Carbon Tool Steel is the finest-grained tool steel available and the finer the grain the sharper the edge. A2 is a newer alloy that will hold its edge longer; the alloying elements that increase edge retention form large, tough carbide particles during heat treatment. It’s a little harder to sharpen and bit more expensive but if edge life is paramount, you can’t go wrong with A2. But if ultimate sharpness and ease of sharpening are more important, high carbon steel will allow you the sharpest edge possible.