The same people that made the AO glass years ago and btw, Schott is based both in the USA as well as in Germany and they make the Phillips Safety glass lens now.
Here are some more links to earlier threads on the AO Cool Blues:
http://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=174890;hl=Schotthttp://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=172513;hl=SchottI have used both, and I think that both of them are equally excellent yet, would purchase the Phillips Safety glass over an older AO Cool Blue any day of the week simply because the price is sooooo much better, and they're basically the same type of glass except that the Phillips Safety glass are actually an improvement of the original design and are manufactured in Germany instead of in the US where they are prohibited from being made with the use of the cobalt additive here.
So don't waste your money on the older and more expensive Cool Blue's when you can purchase a whole box worth of the same technology and in different shades that's now manufactured in Germany for the price of one of the older ones!!! :) :) :)
Respectfully,
Henry