The Xi2 cutter has 440 stainless blades hardened to a Rockwell C rating of 56, and are buffed to razor sharpness. The result is the hardest, sharpest blade you can buy. The classic Xikar shape means ergonomics and power. The exterior is composed of a heavy-duty, yet lightweight nylon fiberglass composite with a metallic color. Cuts up to a 56 ring gauge.