Newly installed and working. So far I give 5 for the optics. I hope it lasts as long as the original 38 year old alternator from my '79 Chevy G20 van that was still charging, but the stock was noisy. I was a bit concerned that a note on the alternator indicated that the internal regulator was set at 14.8 volts, which I think is borderline high. However, I have found that the battery voltage with the engine running is 14.6 volts, which I think is on the high end of acceptable but normal given that I drive mostly short trips.