I'm looking for a dirtbike helmet, wondering what the general consensus is with snell certification on helmets. It seems to me that a dirtbike helmet will see more impacts over its life, so snell could be beneficial from that point. But on the other hand more force is likely to be transmitted than with just a DOT helmet. Thoughts? Also I've found helmets with ECE 22/04, I'm not sure what that rating means, can anyone help me out?