Forged from the finest chrome molybdenum alloy steel-the best choice for strength and durability. Set features a heavy duty blow molded storage case and is fully guaranteed. This set contains 12 METRIC and SAE pieces, sizes: 3/4-Inch, 13/16-Inch, 7/8-Inch, 1-Inch and 1-1/16-Inch, Metric sizes: 17mm, 19mm, 21mm, 22mm and 23mm.