Constant Speed Control = Constant torque automatically delivering more power Professional power up to 5,500 RPM 90 minute cordless runtime with 60 minute full charge time Durable, lightweight, quiet with low vibration and no maintenance Lithium Ion no memory battery prevents overcharging, overheating and only consumes the energy it needs to charge Wahl Bravura Lithium cord/cordless Animal Clipper has new lithium Ion non memory battery technology. It is suitable for all day use with a 90 minute cordless run time and fully charges within 60 minutes, otherwise you can simply plug in the cord and continue to use for however long needed. It is ergonomically designed to fit comfortably in your hand and is lightweight to prevent wrist fatigue. Bravura features Wahl's signature 5-in1 fine tooth blade which easily adjusts between sizes #9, #10, #15, #30 and #40. The blade is ideal for high performance clipping and easy to snap on and off for routine cleaning.