Each PUMA SGB knife is made with 1.4116 German Cutlery steel for extended blade life. Each blade is individually tested to ensure hardness between 55 and 57 and bears the dot of a Rockwell proof mark. The Blackcat 55 is the big brother to the Blackcat 45. The Blackcat 55 features textured G-10 scales and features thumbstuds and a belt clip. Opening the knife is easy due to a spring assist.