Hey guys I made a mirror like this for myself awhile back to monitor my battery voltage and a lot of people showed interested so I figured I'd offer a couple to the community. They are auto dimming/tinting rear view mirrors (meaning when headlights behind you hit the sensor they auto tint, no need to manually flip the mirror) and I installed custom voltage meter display. I can do these Displays in BLUE, RED or GREEN (as pictured below). They work on basically anything with a windshield and battery. Installing is simple, ground and power wire to connect.
If it might tickle anyone's fancy I also have compass display only mirrors and mirrors with compass/temperature display (comes with temp sensor). But these cannot be combined with voltage and are only one color (its like a light green). I'll post some pictures below to show. Prices are as follows
Voltage - $55
Compass Only - $40
Compass/Temp - $65
If you need any help or have any questions just let me know, thanks! I'm located in Pittsburgh, PA