"Technology with an Edge" Speed-Safe torsion bar technology for smooth and easy assisted opening. Quality 420 high-carbon stainless steel blades with 55-57 Rockwell hardness rating. High-tech handle materials including injection-molded Polyamide and stainless steel. Handle - Polyamide. Blade: 2 1/4". (5.8cm) partially serrated (model 1620ST). Closed: 3 1/4". Weight: 2.3oz.