So HifiMan made marketing campaign on his Stealth Magnet feature, what are just a slightly rounded magnets, probably there are other adjustments in the driver that are not mentioned because of the different impedance of the Stealth headphones.
So these Stealth Magnets result in a more accurate and precise instrumental image, but with smaller sound stage unfortunately. By what I can see the Stealth Magnets phones currently are:
HE-6SE
HE-6SE-V2
HE-400SE
EDITION XS
HE-1000SE
Arya 2022 Stealth Magnet