Pistol-grip drills position the user's hand behind the bit-holding chuck to keep the tool steady and control the amount of pressure applied to the bit during drilling and driving. They provide ergonomic handling when working in a range of positions on vertical and horizontal surfaces. The pistol grip has a trigger switch that is pressed to activate the drill. Corded drills plug into an outlet to allow longer run times than cordless tools for applications where portability isn't a concern. Cordless drills run on batteries, so they are more portable than corded drills and allow use where a wired power source is unavailable. Gas-powered drills are powered by a gasoline engine for outdoor drilling.