This master size crochet hook set comes in a durable vinyl case zippered on three sides, so it lays open flat. This set contains both aluminum and steel hooks in a wide assortment of sizes. Details: 25 piece set Includes steel and aluminum hooks Includes vinyl storage case Size information: Steel hooks: 00 (3.5 mm) 0 (3.25 mm) 1 (2.75 mm) 2 (2.5 mm) 3 (2.10 mm) 4 (2.00 mm) 5 (1.9 mm) 6 (1.8 mm) 7 (1.65 mm) 8 (1.5 mm) 9 (1.4 mm) 10 (1.3 mm) 11 (1.1 mm) 12 (1.0 mm) 13 (.85 mm) 14 (.75 mm) Aluminum hooks: D-3 (3.25 mm) E-4 (3.50 mm) F-5 (3.75 mm) G-6 (4.25 mm) H-8 (5.0 mm) I-9 (5.5 mm) J-10 (6.0 mm) K-10.5 (6.5 mm)