Steve, My neighbor a few doors down took whitewater helmets to the extreme: his were the first to be approved by Snell motorcycle standards. In researching their design, he tested every other helmet on the market, and found some pretty interesting, and frightful, results. I wear one of his helmets, called River Tools, and have definitely taken hits that would've cracked lesser helmets. I know he uses a kevlar/s glass combination (in their respective layers where tension/compression are the dominant forces). Equally important, however, is the padding/suspension system used inside. That part of the helmet is where most commercially available helmets fall way short. Minicell, for instance, according to my neighbor, is NOT good at managing the kind of energy a helmet lining deals with. I'm going to get his e-mail address for you, and you get get the dope straight from him. Oh, and though he doesn't make his helmets anymore, i often ask him what the next best thing is these days. Oddly enough, it's pro-tec's "aggressive skate" helmet available at Big 5 Sports for around 40 bucks. Keep up the research, man, there isn't anything on the market as good as what can be made, if its got the right numbers and craftsmanship built into it. Brandon