I wear AGV helmets almost exclusively (well, that or the Arai Profile), the Stealth seems bigger to me than the rest of the AGV models. I wear a medium in most AGV models and a Med-Large Ti-Tech (which has an especially small shell), but a medium Stealth is huge on me. Not that it matters if you are actually going to try before you buy, but if you are thinking of mail ordering a helmet then a Stealth might not fit like you expect.

Of course, it is possible that I just happened to try on one that had been miss-labeled or someone had changed around the pads. I wasn't really serious about buying one so I didn't really look too closely, but I believe I did try on two different ones and they were both very large in comparison to the marked size.