Summary: -Torque open ends. The primary difference between Flank Drive Plus and Opti-Torque is that the Flank Drive Plus profile exists on both sides of the open jaws and the system works both ways: http://www.expeditionexchange.com/snap-on/DSC05771.jpg The Opti-Toque profile works only one way. If you want to wrench hard the other way with the Opti-Torque, you have to flip over the
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