The SCORPION EXO-400 is our BEST SELLER. The EXO-400 uses the Everclear Fog Free Shield and same KwickWick Super Plush Liner found on the EXO-700. The ventilation system on the EXO-400 flows just a tickle less air than the EXO-700, most would never notice the difference (many of us have ridden in both and don't notice a signifigant difference). The main difference is shell construction, the EXO-700 is a fiberglass shell and the EXO-400 offers a polycarbonate shell. The weight of the two is near identical on our scales.