A small addition: The charging box is not absolutely necessary, but super practical if you want to take the headset with you in your bag. The charging box protects the headset well and also has an integrated battery for recharging the headset. As I only use the headset occasionally when travelling, I only need to recharge it every few weeks.
The headset has been on the market for a long time, but in my opinion it is still a great device and I would buy it again at any time. The headset has great noise cancellation, for example, you can make calls on the station platform when a goods train rushes past and even when cycling despite the wind.

Yes, you can charge the headset in the box, and there's a micro USB port on the back of the headset. The battery life in the box is more than enough for a day's work, with calls and video-conferences. Personally, I put it on my ear in the morning and take it off at night: no worries.
There is an on/off button.