Features and Benefits: For standard and deep lengthsForged from CR-MO alloy steelSize range is from 3/16 in. – 9/16 in. and metric impact sockets from 4mm – 15mmBlow mold storage case This is a 48-piece impact socket master set. It is 1/4 in. drive. It includes metric and fractional impact sockets. WARNING: This product can expose you to Nickel (Metallic) a chemical known to the State of California to cause Cancer. For more information go to www.P65Warnings.ca.gov.