You're, if I can be frank, wrong. The difference between the two different types of headphones is the amount of isolation the headphones provide. Open back headphones provide minimal, if any, isolation. Closed back provide significant sound isolation. This difference was outlined by a sibling comment which was sadly downvoted.

These are simply open backed headphones that use a different method of setting the distance between the driver and the ear. That's all.

Please see my other comment and dial back the hostility a touch. You are in fact mistaken.

Here's a whitepaper on the driver technology they're using: https://www.tectonicaudiolabs.com/wp-content/uploads/2019/02...

This is the first time I'm aware of anyone has used this class of driver for headphones, and they have novel properties that support their idea of a spaced nearfield monitor rather than an open or closed back cup.

For "off-ear" headphones there are only 3 different ways to build them: closed, open or half-open, solely based on amount of air flow given to a driver (and the type of driver doesn't matter).