The Grainger 16T527 is a Westward 3/8-inch drive deep impact socket set. This 12-piece set includes sizes ranging from 10mm to 19mm, providing a wide range of metric sizes for impact wrench applications. The sockets are made from chrome vanadium steel for durability and have a black phosphate finish to resist corrosion. According to the product details, these impact sockets are designed for use with pneumatic tools up to 1,000 ft-lbs of torque. The set comes packaged in a molded case for convenient storage and organization. With a broad range of metric sizes, durable construction and protective finish, this Westward deep impact socket set is well-suited for automotive and industrial use.