Because of the wind noise that you experience while riding, it is normal that you will not be able to hear voice navigation prompts from the device, especially with a helmet on. Garmin addressed this issue correctly and has placed one headphone jack under a weather cap at the left of the device and used a A2DP compatible Bluetooth chip, which enables you to stream the voice commands or your MP3 music/books directly, with stereo sound.
Compared to other budget and intermediate level products from Garmin, the Zumo 660 features 3-D buildings, lane assist, a junction view, and a digital fuel gauge, letting you see all the information about your trip and your vehicle at a glance.
The Zumo 660 has millions of Points of Interests (POI) and you have the option to add your favorites. You can also save your routes and share them with your biker friends or view your tracks in Google Earth.
Speaking of Google Earth, the Zumo 660 has the feature to download Panoramio images to your device and navigate to the points with ease. You can use Google Maps for this purpose.
If the built-in memory is not enough for your music, routes, and tracks, you can always expand Garmin’s memory with microSD cards.
The Garmin Zumo 660 also features a “where am I" button, which immediately shows your location in latitude/longitude and shows the nearby addresses of hospitals, police stations and gas stations.