The "H" series of Leatherman knives was introduced in late 2006, and retired in 2008. All are lock-backs with a blade release lever on the rear of the knife. They are about 15mm (1/4") longer than the "C" and "E" series knives. "H" knives have 420HC stainless steel blades. Even numbers are plain blades, and odd numbers are partly serrated.