Available in a various sets, R.B.R.T SAE and Metric Combination Wrenches from Mac Tools are designed to be used on new and damaged fasteners. They are capable of gripping and turning 60 percent rounded fasteners with the open end and 80 percent rounded fasteners with the box end. Compared to existing Mac Tools wrenches, these combination wrenches provide up to 2x more torque. The combination wrenches have a I-beam design for maximum strength and comfort, a double offset head for ease of use, and a polished finish for easy clean up.