Faster going, better stopping.
HED's Jet 9 Plus Black Carbon Disc Brake Wheelset goes straight to the extreme of road braking, upstaging questionable carbon braking, alloy rim braking, and even the vastly improved Jet Black brake track with the superior stopping power of disc brakes. Disc brakes also virtually ensure that carbon wheels will never violently deform after reaching the glass transition temperature as a result of constant braking on long, hot descents.
HED also knows that anyone interested in 90mm rims is looking primarily for faster speeds, not faster stopping, and HED's Stability Control Technology (SCT) ensures that the increased aerodynamics don't come with handling that throws you around in crosswinds. SCT involves rounding the rim's spoke face and sidewall profile to reduce force put on the wheels by side winds at 0-15 degree yaw angles. While 90mm rims will obviously never handle crosswinds like box clinchers, the rounded inner face of SCT design does give the deep dish monsters more intuitive predictability than wheels with a true NACA airfoil cross section.
The Jet 9s also feature HED's signature 25mm C2 rim width, which increases tire volume and contact patch for lower rolling resistance, more grip in corners, and a more vertically-oriented tire sidewall that is better able to deform around irregularities in the road surface — all of which translates to being able to run a lower PSI for increased comfort without sacrificing efficiency.
The wheels are finished with HED's own Sonic Black hubs, which run ABEC5 bearings on oversized axles with wide flanges for a stiff, lateral bracing angle and more efficient power transfer. The rear hub has high flanges and a capped grease port, so you can power wash and re-lube the wheels as needed. Both quick-release skewers have titanium shafts, and the ratchet ring in the rear hub is also titanium.
Please also note that HED recommends a maximum tire pressure of 100PSI.