Forged from the highest quality chrome molybdenum alloy steel for long life. Packaged in compact blow molded case for durable, convenient storage and transport. Fully guaranteed Set includes: SAE - 3/16", 7/32", 1/4", 5/16" (8mm), 3/8", 7/16" and 1/2"; Metric - 4mm, 5mm, 6mm, 7mm, 10mm and 12mm.