Im my profession as an airline pilot, I have purchased numerous pairs of sunglasses in my 25 years in the air, and these are simply the best I have purchased. I'm sure glass technology has changed a bit, but for the money, these are far superior to glasses I've paid over $400 for.First, they are not polarized due to the polarization of the flight deck windows and displays in the flight deck. As you know, if you wear polarized glasses and look thorugh a polarized windshield, you get the "oily" smear of colors. Worse yet, if you wear polarized glasses in the flight deck, and rotate your head to the right or left, the polarization of both the glasses and the displays will cause them to black out at extreme angles. Obviously not a good scenario. If, on the other hand, you need the polarization for water activities, snow skiing, etc, then I would most definitely purchase the polarized version.Next, these glasses seem to have x-ray capabilities in hazy, smoggy, overcast sky conditions. Also, when looking for other airplane traffic at altitude, these glasses allow me to be the first of the 3 pilots to actually spot the other airplane the controller has pointed out.This is especially helpful as most of my flying is done in Europe, which is notorious for hazy sky conditions.Lastly, they come with a hard sided case which protects your purchase and also fits handily in the flight bag.Overall, a great pair of glasses at a good price. Yes, you can pay more, and I have. But I'm not sure you can get a technically better pair of sunglasses.