Here's the website:

Here is a link that might be useful: winter gaurd

Remember that Certainteed isn't the only company that makes this kind of product. They come in a couple of colors in the gray to black range. In any case, they are thin, rubberish, and very sticky on one side. Not at all like traditional roofing felt. The manufacturer/brand name is often clearly printed on it too.

"Ice & Water Shield" is a trade name of WR Grace (now Grace Construction Products). They invented and have been making this type of waterproofing membrane for over 40 years. It is a flexible self-adhering modified-bitumen (asphalt) membrane with a polyethylene sheet on the top face. It is the same as Vycor 40 window flashing but with a non-slip surface for use on a roof. They also make masonry through-wall flashings, butyl-based membranes, and vapor permeable liquid-applied membranes.

CertainTeed and other roofing manufacturers have finally gotten around to selling a copy of Ice & Water Shield as part of their "roofing system" in order to sell it.

I strongly recommend staying with WR Grace products and carefully following their recommendations for roofing and window detailing instead of those from window and housewrap manufacturers; Grace is run by waterproofing pros in an industry increasingly dominated by marketing and advertising people. When designing major buildings I have run every detail by their reps and they have never let me down.

Here is a link that might be useful: WR Grace roofing underlayments