Drop forged alloy steel. Designed with trucks and hydraulics in mind. Also very useful working on new cars and pick-up trucks Sizes included: 3/4", 13/16", 7/8", 15/16", 1", 1-1/16", 1-1/8", 1-3/16", 1-1/4", 1-5/16", 1-3/8", 1-3/16", 1-1/2", 1-9/16" and 1-5/8".