very convenient! I hate it when car ferry to turn the wheel, trying to shift and then have the phone on your ear. Since I'd always step out and miss the people left and right a. But with such a discreet and practical device at the ear I can make calls and have your hands free. Whether it's driving, working or whatever. Battery performance is ME good. I miss only occasionally a button for volume. The must be set directly on the mobile phone. But a real shortcoming that is not well.