I use this Craftsman model..
http://www.amazon.com/Craftsman-Cord.../dp/B002X0A40G
It certainly isn't strong enough to tighten/remove a 7/16-1/2 lug nut from a fully engaged position or a final torque position. BUT it is a great tool for a guy like me who has to change tires 8 times a day when he races...(no trailer, I drive to the track)
Kris