1.can be used as a headset
A headset is one headphone or pair with a built-in microphone. Headsets can be used for apps that require communication i.e. Skype, games with voice chat, mobile phones, etc.
3.control panel placed on a device
There is a control panel on the device body, so you can easily access the volume control or remote without having to interact with a cable or another device it's connected to.