Triads my friend. They use the Cartel base with the C02 highback (least that's what I'm told).
The CO2 highback is different. It uses the real mesh as opposed to the injected plastic on the triad.
Are the C02's a lot stiffer than the cartels or triads?
The CO2's are very stiff. Burton may only rate them 1 point higher than the cartels, but they are very stiff compared to the cartels. Not that the cartels are too flexible (I have a pair and they are just how I like em, not too soft not too stiff). The other main advantage of the CO2's is that they weight next to nothing due to all the Carbon in them. So if you want a very stiff and very light binding then get the CO2, but if you want a still pretty light binding and a little more flex then get the cartels.