Behind the left ear is an NFC chip. If you think his smartphone on the verge of the Bluetooth is enabled and the connection is established automatically. Before you have to turn on only the headphones, this is done by long pressing a button. It then begins to flash. Once the wireless connection is established, it begins slowly blinking.
The built-in microphone is also very handy and works well. Calls you take the easy way by pressing a button. The button serves to adjust the volume, you also used the song to change where you pressed two times up or down. The whole can be loaded via microUSB connection. I use it almost 2 hours a day and charge it every two days in order to be sure that the battery is empty. I also keep the Jack-Jack cable here, if it should happen. So far I have but never used it.
What is missing, in my opinion, is a lock button. It happened to me a few times that my headphones on their own went into my pocket, because something has pressed against.