The Skil 7.2-volt lithium ion power wrench allows for fast tightening, loosening and driving at the pull of a trigger. Lithium ion power allows this tool to hold its charge up to 18 months, so it's ready to work when you are. Skil Lithium Ion Power Wrench: 7.2-volt lithium ion battery holds a charge for up to 18 months 100 in lbs. of torque 200 RPMs 1/4" drive head with forward and reverse.