Crucible Industries' CPM REX 121 is a high-vanadium, cobalt-bearing tool steel designed to offer the greatest wear resistance, attainable hardness, and red hardness available in a high speed steel. Created to bridge the performance gap between high-alloy tool steels and carbide materials in demanding industrial applications, when applied to knife blades, it offers extreme hardness and unequalled edge retention. This unique expression of the popular Sage 5 showcases REX 121's remarkable properties in its full-flat-ground, satin-finished blade. All other features of this knife are consistent with the proven Sage 5 platform, including nested, skeletonized stainless steel liners, a high-strength Compression Lock mechanism, and a reversible wire clip that supports ambidextrous tip-up carry.