U.S. only for newegg. The 100mm is no more unusual then the 140mm front intake fan on the case here or the 250mm seen on another model by the same brand seen at
http://www.xoxide.com/aerocool-extremengine-3t-black.html
The bulk of case fans are generally 30, 40, 50, 60,70, 74, 80, 90, 92, 97, 120mm, and even 130mm as well as 140mm with the occasional 70mm or 100mm thrown in. Most of the odd sizes are seen when using a fan adapter to run a slightly larger size like a 100mm on a 80mm opening.
