Filter Cobra to a soft flex and you are left with its recent mainstream heads plus a long tail of older King Cobra stock.
The DS-ADAPT MAX and the Darkspeed MAX are what you will see most of the current range. Both are forgiving and both are worth considering, though neither is the ultralight build.
The ultralight builds, AIR-X and F-Max Airspeed, are what most people here actually want, and the hardest to find. The AIR-X in particular is worth watching for, because it pairs the light build with an offset head.
Older King Cobra and S-series heads turn up frequently and cheaply. A good number of them were sold in a soft flex as standard, which is why they persist here. They are worth a look if budget matters more than face technology.