The charging case is not required to charge these headphones. All it is is a case with a built-in battery that allows you to charge the headphones when you're away from the outlet. The SoundSport Wireless earbuds come with a small microUSB cable that you can plug into any computer, AC outlet, car USB port, or anything else with a standard USB port for charging. So they already come with everything you need to use and charge the earbuds. The optional case is not required. I've used the USB port on my monitor at work to charge my earbuds as well as the USB port on my MacBook at home, and the chargers that came with my iPhone and a Bluetooth speaker (from another brand) that I have. They all charged the earbuds just fine.