CPM MagnaCut is a high-performance premium steel that hits the sweet spot of qualities that make a superior knife blade. It has excellent edge retention, toughness, and corrosion resistance. It is a relatively new steel on the market and is an excellent choice as a knife steel because it retains its edge so well and is easier to maintain. Leatherman has chosen to use this steel in the Arc to give our users the best possible cutting performance on the best multi-tool we’ve ever made. It’s also particularly well suited for harsh conditions and wet environments.