Martor Knives & Blades Retractable knife 621749 - Martor 52500110.02, The Martor 52500110.02 is a retractable safety knife designed by Martor. It features a SECUNORM 525 blade ideal for precision cutting tasks. This knife is typically used for safely cutting through packaging materials in industrial and commercial settings. Martor 52500110.02 SECUNORM 525 Safety Knife 18mm Cut Aluminium Handle