This impact wrench has several handy features, for example that it's brushless. It runs on a rechargeable battery, so it's completely cordless.
From Amazon
Milwaukee M18FIW2F38-0X Battery Socket Screwdriver XXX 4933478650
Powertool World
Milwaukee M18 FUEL FIW2F38-0X 18v 3/8" Impact Wrench With Friction Ring Body Only In Carry Case
This product is also available at 1 unverified merchant.