"Impact sockets are forged from high-quality chrome molybdenum alloy steel for durability and superior strength. Patented sidewall drive sockets apply force to the walls of the fastener instead of the points, resulting in longer fastener life. Laser-etched, hi-visibility markings allow for easy readability. Meets or exceeds ANSI and government torque performance specifications. Pieces qty. 8, Specialized Pieces qty. 0, SAE Deep Socket Size in. 5/16-3/4, Material Type Chrome molybdenum, Measurement Type Standard SAE, Storage Type Plastic case, Point 6, Drive in. 3/8."