Stock mirror from my '85 4runner. We got up to around 8,450ft elevation this weekend to camp, and escape the dense smoke from all of the forest fires. I enjoyed Geeking out with my altimeter, angle device. It is surprisingly accurate. Everything worked well, and even with uphill, against the wind driving, where "Cruise control" was 4th gear floored, doing 55 to 60mph, we got 22.5 mpg on this trip. Impressive, if I did the math correctly..........add 10% on speedometer, but subtract 10% on odometer??? Otherwise, the math says 27mpg, and that would be rather impossible with my set up, I believe......