Good sound quality and noise cancellation, no buttons for volume control

+ Good sound. The interlocutor is clear and loud enough. A slight scratching can be heard every now and then and the voice sounds slightly muffled, but overall that's whining at a high level. Even you yourself will be well understood, often remembers my opponent only that I telephone with headset, if I point it out.
+ "Total Noise Blackout". Finally, a noise reduction, worthy of the name. Background noise is very well filtered. Even with phone calls while driving the voice also comes with 120km / h without noise to the interlocutor.
+ Battery life. I did not handgestoppt but given six hours to come back.
+ Good range. I can move around freely in our 90 square meter apartment and had all reception.
+ Good workmanship.
+ Fast and easy coupling.

o comfort. The headset is light, holding in my ear but not, so I have to use the bow. This is after some time at the expense of comfort. Certainly an individual thing.
o Button for Google Now / Siri. Works on Android with AIVC or other language assistants. Nice gimmick, not necessary for me, but surely also a matter of opinion.

- Lack of volume buttons. Probably for reasons of space, there are no buttons to adjust the volume to. For this, there remains only the handle for Smartphone, what I feel to be extremely impractical.
- Fummeligge USB cap. The tiny cap that must be removed when the Stealth is to be loaded, is unnecessary in my opinion and also not really succeeded. Especially when closing it is a haklige matter until it finally is right again and it remains.

Conclusion: I would highly recommend this headset, especially if attention is paid to good voice quality and functioning noise reduction. Before that I had tested the Jabra Classic and the Plantronics ML90, both could not keep up with the Spirit in these points, but playing in a different price range. Also the battery life, the scope and processing speak for the Stealth.
The only real drawback in my opinion the lack of volume keys. The button to activate the Voice Search is indeed nice to have and works well for me with AIVC, but the function I need in everyday life rarely. Nevertheless, the headset is worth the money and stands among the tested by me clearly visible.