$64.99 Ingersoll-Rand W7152 20-Volt 1/2-Inch Cordless Impact Wrench - Bare Tool - Walmart.com - Walmart.com
DEWALT 18-Volt NiCd Cordless 1/2 in. Impact Wrench (Tool-Only)-DW059B - The Home Depot
BOSCH 1/2 Cordless Impact Wrench Kit, 18.0 Voltage, 500 ft.-lb. Max. Torque, Battery Included 
