An improved, high-carbon (HC) form of 420 stainless steel that works well with high production tooling. 420HC's strength is optimized in Leatherman multi-tools by heat treatment. , A high carbon, high alloy, and corrosion resistant stainless steel that holds its edge three times as long as 420 stainless steel. This steel is used on some premium Leatherman tool features, such as knife blades.