Replacement knife for Muller Martini Zenith 3671 Swing Cut paper cutting machines. We offer the best quality cutter knives for these cutters in several styles / locations, including these top front and top side knives for the left and right sides. These durable Jayhawk Diamond Cut replacement blades are manufactured with high speed steel (HSS); a 50/50 blend of standard grade steel and high speed steel, which is comprised of 18% tungsten. These solid, hardened D2 steel blades offer premium wear-resistance for a longer blade life. These Jayhawk Diamond Cut blades are manufactured to not just meet, but to exceed OEM specifications, ensuring extreme precision and longevity.