The 16-Piece 3/8" Drive 6-Point Metric Impact Socket Set (46-891) by Armstrong includes a variety of sized sockets for a variety of applications. These sockets are manufactured from high alloy steel using the most up-to-date manufacturing process and heat treat for greater strength and durability. The radius corner design engages the flats of the fastener, not the corners, providing up to 15 - 20% more torque while reducing fastener rounding.