The STANLEY STMT71650 60pc Socket Set is constructed of high-allowy steel and heat treated for increased performance. Stanley sockets feature the proprietary Max-Drive design, a unique radius corner design which provides 15 percent more torque, making it easy to tighten fasteners and simplifies the turning of rounded corners. This technology helps reduce fastener wear without contact on the outer 5 percent of the fastener, so fasteners last longer. This helps reduce slipping on frozen or rusted fasteners. This 60pc socket set meets or exceeds ANSI standards for sockets and ratchets.