If airex is used in CARF wings, then it is probably the R70.55 in roughly 1/8 to 3/16 thickness. I never knew what it was but I think that is it. The skin construction of the CARF Flash wing is very similar to the Bandit ARF wing. For the skin, basically structural foam sandwiched between 2 layers of glass. Weight of glass used I would guess totals 5oz maybe. The spar and rib structured is glued to this with a epoxy/micro balloons type mixture lined with carbon tow. The use of the epoxy/micro balloons adhesive is quite liberal. The Flash wing is so strong it will hold up to moderate/aggressive flying even if the adhesive is compromised (fractured) over, I would say 25% of the wing....