I do a lot of freeway driving and I've tried 2 of these speaker phones with myTreo and the noise cancellation feature is poor. It works fine below 45 mph but the faster I go the more my callers complain about the road noise. Also you have to turn off Bluetooth on the phone when you turn off the speaker phone. The phone thinks it's still connected to the speaker phone,it will show that it's not connected to any Bluetooth devise but keeps the phone mic and speaker on mute until Bluetooth is turned off.