I made a long message about cobbs lights a couple months ago.
I have both lights, the 250 one and the 40 one. The $250 one works just as advertised, works without covering the windows and spots are very visible.
The 40 dollar light throws out so much visible blue light that you can't see many spots. So just to see I put on some yellow safety glasses. The safety glasses makes the 40 dollar light nearly as good as the 250 dollar light. So much so I purchased two more and made a kit that contained two pairs of glasses and the flashlight in a small case that I purchased on amazon. Looks very csi and now all my vans have a light.