Review on Car Head-Up Windshield Display - OBDII HUD Head Up Display Color LED Projector Speed Warning System for Car Trucks by Jason Morrison

Pretty good for the price. If you're using this in an 18 year old car, not sure if the car's ECU or device is slow, but it takes about a second to catch up. Overall I like it and it seems to work well. Update: I just received a 2012 Mazda 3 and put it in there. I haven't used it in months, it was disabled but it seems to have saved all my settings which seems pretty accurate for this machine too. In this car, however, he reacts much faster. In fact, it shows the real-time speed, the RPM is slow, but no matter.