I would have preferred to find this type of helmet bluetooth transmission rather than radio, but all Bluetooth headsets are designed to be mobile and therefore well hold up, or I can not stand to have the compressed ears. This greenhouse Sennheiser still too much for my taste, but still comfortable nonetheless. I find the excellent sound quality, long ago I did not have a helmet as faithful, as to the scope, in the house, 10 meters wide, including with a stage. Autonomy is correct, 16-18 hours with good quality batteries (not included for the transmitter, which I find particularly paltry from Sennheiser). I am happy with this purchase.