Spline Sockets
A spline socket is also known as a 'triple square socket' or an 'XZN socket', and is a socket that is designed for tightening/untightening fasteners which have a 12-point spline head. Spline sockets have internal splines that run up the socket, providing more contact area to the fastener, which allows for more torque to be transmitted, whilst also reducing the risk of rounding.
A spline socket is used with a torque wrench or ratchet and can be used to also fasten 4-point, 6-point (hex) and 12-point (bi-hex) fasteners. These sockets are widely used in the automotive and aviation sectors, where high torque is required to be applied to fasteners.
