The Wahl Clipper Lithium Ion® Trimmer for men is the world's first grooming device with Lithium Ion Technology. It is the most advance rechargeable battery technology available. It's lighter weight, has almost no charge loss in storage, is environmentally smart, and has no memory issues. Best of all, it provides 3x the run time, 2x the torque, a 1- minute quick charge and 1-hour full charge which standard NiMH/NiCad trimmers cannot do. Wahl Guaranteed to Trim and Shave Better.