In an effort to find the best impact drivers, I assembled 12 promising impact drivers and then tested each tool in my workshop in a side by side showdown that involved using each one to drive in screws and bolts and bore holes. With its 24-volt battery, Kobalt’s XTR impact driver offers power similar to higher-end impact drivers but at a much lower price. It won’t match the raw power of some impact drivers, but it’s one that can handle most homeowner’s demands. Impact drivers also have two to four speed settings that limit the impact driver’s maximum speed when working with smaller fasteners. Thomas HenggeKeep in mind that 18-volt and 20-volt impact drivers produce exactly the same amount of power.