The 82 XTI uses Amphibio technology and Waveflex construction for longitudinal flex and torsional rigidity. It' s constructed with two sheets of metal, has an RTS sidewall and a laminated wood core. It' s 82 in the waist. The tips of the new Amphibio skis are tip-rockered on one edge, but not the other. You could call it "twist rocker." The idea is to have aggressive camber on the downhill ski with a looser feel on the uphill ski. Testers suggested mixing and matching to suit conditions-rockered edges inside for soft-snow, cambered edges inside for hard snow. Waveflex cores use a wave pattern (think corrugated carboard) to keep them flexible longitudinally yet stiff torsionally.