All Xi Cutters feature 440C stainless steel blades with a Rockwell HRC 57 rating: they will cut a 54 ring gauge cigar in half. Depending on how much cap you cut, they will cut up to a 60 ring gauge cigar. The differences between the Xi series is the bodies. Xi1 are all aluminium, the Xi2 are a lightweight, nylon-fiberglass composite and the Xi3 are some of the more exotics like carbon fibre, woods, and other metals