How do you charge dr dre headphones?

Only Beats by Dr. Dre Wireless and Beats by Dr. Dre StudiOS require batteries. To charge Beats by Dr. Dre Wireless, you require the USB charging cable that came with them, plug one end into your headphones and the other end into a USB port. Beats by Dr. Dre StudiOS require two AAA batteries. To install/remove the batteries, grip left ear cup using two hands, press down and twist counter-clockwise approximately 1/8th turn. All other Beats by Dr. Dres don't require batteries.