Review on Universal Car HUD Head Up Display With Digital GPS Speedometer, MPH/KM Acceleration Time, Compass, Altitude & Driving Distance Monitoring - Overspeed Alarm HD LCD Display For All Vehicles by Isaac Maze

I'm sorry about the one star ratings.I don't know what to say except it does exactly what I wanted it for: COMPASS AND ALTITUDE!BE AWARE mountain people, it only goes up to 10,000 feet BUT IT IS HAS VERY CLOSE ACCURACY WITH ALTITUDE.Our Airport 4 miles from me is 1132 feet above sea level. My house is up the hill a bit and is 1157 feet altitude.Also, once you drive the first time the compass works perfectly in the first 10 to 20 feet!. It does have the SSW, SSE, NNW NNE which shows up as a north and west line for NNW.this item is very light and you'll need to hide the cable or purchase any micro USB to male USB A to connect to a phone charger.Note: If you need direction/compass on a non-moving place, this is not for you.For my base model car? It's perfect.See initial pictures I took. I drove 60 miles and it worked perfect.My speed was off only 1 MPH! WITH NO SETUP.! My car may be off that!So, I'm still not sure about the one star reviews. Maybe defective units?VERY Happy with mine.And remember, altitude is only UP TO 10,000 FEET.CHEERS!