http://www.stormcam.org/gps-visor/
I StreetPilot c330. Everyone knows how to reduce the glare of the sun (the screen is not like that option)?
Garmin StreetPilot C310, C320, C330 GPS all have this problem that can not see well in bright sunlight.
I would get a strip of canvas set on top of your windshield, I have that I can see my screen indash better. Go to your local place tinted windows and they will do for you. It a normal thing to have done.
Visor de Servicios Web Cartográficos (WMS) y GPS desde dispositivos Móviles