Stanley Proto has introduced its first ever line of spline sockets. The new line includes 55 SKUs, in '", 3/8" 1/2", '" and 1-in. drive models. Standard depth and deep sockets are available in the three smaller drive sizes. The sockets can be used on spline fasteners, as well as on four, six, and twelve point fasteners. The spline socket/fastener system offers higher strength in a more compact profile than conventional fasteners, making it common on military equipment and commercial aircraft.