IMO, 509 does not offer a polarized lens suitable for the darker conditions of heavy overcast days. I own their brown polarized and their yellow polarized lenses for my Sinisters. The brown I bought for bright sunny days, and it's awesome for that purpose. I had high hopes that the yellow would be as good for flat light conditions and bought them a month ago, and immediately upon taking them out of the package I knew that the tint was too dark. It simply blocks too much light transmission, and is nearly as dark as the polarized brown lens I already had. I decided to give it a go on my next ride anyway, which was in flat light, heavy overcast, snowy conditions. Frankly, that lens sucks for that condition. It's far too dark. I wrote a note to 509 suggesting they consider lightening up that lens, because IMO a light (very light) yellow tint with polarized coating would be awesome for flat light days because it would improve visual perception of terrain features. 509's response to my suggestion was I was the only person who had ever complained about the tint, although to their credit they did offer to take the lens back. I've opted to keep the lens as a backup for bright light conditions, but will be looking at other manufacturers besides 509 to find either a very light tint yellow or rose with a polarized coating that allows high light transmission for those dark flat light days.
