I've got two of the Xi2's. These cutters (made in Solingen, Germany) have blades hardened to a Rockwell C rating of 56. The result is the hardest, sharpest blade they claim you can buy. The body retains the classic XIKAR shape and features a lightweight nylon fiberglass composite in metallic colors including blue, green, gray, burgundy (flat) and now, black.
The earlier Xi has an aluminum body that encases HRC50 stainless steel blades ...
Personally ... I never use my Xikar's much. Too awkward for me. I prefer the Palio cutter, wich was made by a company that designs and manufactures surgical equipment. Far superior in my opinion ... you can cut thin slices off with such precision, they look like miniature redwood stepping rounds ...