You didn't look too hard:
"AIM+ Shell Construction (Snell M2010-Approved)
SHOEI's proprietary AIM+ technology combines fiberglass with organic fibers that are so strong they can only be cut with a laser. The end result is a stronger, lighter shell that will absorb and distribute the force of an impact safely and efficiently."
More here: SHOEI North America | Safety-Active Safety
Arai says they are "fiberglass based," (which is not the same as saying they are 100% fiberglass and resin) but go into no further details. Nothing unusual here. I know of very few manufacturers who use proprietary materials and construction who give out the details. WHY does Arai still use fiberglass-based shells?
Personally, I don't think my Shoei Quest is the "safest" helmet out there. I think it's likely to about as safe in my fairly normal use as anything else I can buy. But it's more comfortable and better ventilated than most, which means I'm not riding around sweating or thinking about how my head hurts, which makes probably makes a lot greater difference to my real-world safety than the minor differences in safety between one SNELL rated helmet and another.
I tried the comparable Arai (RX-Q) and found it to be double the price and didn't fit as well. Signet-Q fit more tolerably, but also not badly. Didn't think about colors at all, as it's plain white.
