It's Ironman branded, but, is identical to the K Swiss shoe of the same name, but without the Ironman branding on them.

They are truly different then the K-Ona which is also a lightweight trainer. The Ultra-Natural Run II and the K-Ona are both 9-ounce shoes, so there is no difference in weight. They vary mostly in the upper, which I found very comfortable and snug.

But, for a shoe that is made to mimic a more natural running gait, I find them a bit high around my ankles. The shoe touches my maleolus (the Kathy Bates bone, if you remember Misery), which is certainly not comfortable on a longer run. This unnerving feature also blocks my ankle flexibility.

The outsole is flexible, but, also again not as flexible as I would expect from a style designed to mimic or accentuate a natural running form. I find the K-Ona even more flexible than the Ultra-Natural Run II.

It's not a bad shoe, but, is it ready to do battle on an even footing with a Nike Free or a Newton? In a battle of Neutral lightweight "free form" models, no, not yet.

Still, it's one of the coolest post-race shoes going. But, I don't think that's what K-Swiss is aiming for.