Surgical Design™ Royaltek™ Carbon Steel Scalpel Blades are made from high quality carbon steel and sharpened to perfection. 10 series blades fit 3, 3L, 3 Graduated, 5B, 7, 9 B3, and B3L scalpel handles. 20 series blades fit 4, 4L, 4 Graduated and 6B.