DEWALT DCD939KX 14.4-Volt 1/2-Inch XRP Hammerdrill/Drill/Driver XRP extended run-time batteries provide long run-time and battery life Patented 3-speed transmission matches the tool to task application for fastest application speed Heavy-duty 1/2-inch self-tightening chuck tightens throughout operation providing superior bit gripping strength High power, high efficiency motor delivers 310 unit watts out of max power for superior performance in all drilling and fastening applications