SK Hand Tool 89493 13mm x 15mm Stubby Flexible Double Box Universal Spline Metric G-Pro Wrench Works on various types of fasteners, spline, 6 point, 12 point, 50% rounded, torx and square Patented 90 teeth design 5 degree effective swing arc Non-slip feature on the open end can be used on damaged fasteners that are up to 70% rounded. Lifetime Warranty