Review on ACECAR Upgrade T800 Universal Car HUD Head Up Display: Digital GPS Speedometer with Compass, Latitude and Longitude, Speed Test, Brake Test, Alarm, HD LCD Display for All Vehicles by Brett Zhu

Easy as pie! I plugged it in, did a quick test, then taped it to the dash with double sided tape and it was ready to go. I know this is true because sometimes if my speedometer decides to work, I have something to compare it to. It's a little light when it's dark; I'm not used to LEDs, maybe that's why. It's as simple as it gets. I didn't bother to read any instructions. The update stopped working within a week; must be sent back. Perhaps it's the dual adapter that causes this to fail from time to time. To update. I stopped using the dual adapter; GPS now works 90% of the time; if it stops working; I plug and unplug, wiggle, etc.; It could be my lighter 2002 car. Who knows.