Chrome molybdenum alloy steel for long life Ideal for work in tight spaces Reduces wear on fasteners Industrial strength, double latch blow molded case Set includes: 1, 1-1/16, 1-1/8, 1-3/16, 1-1/4, 1-5/16, 1-3/8, 1-7/16, 1-1/2, 1-9/16, 1-5/8, 1-11/16, 1-3/4, 1-13/16', 1-7/8, 1-15/16 and 2.