Headphones

MEMS means "Micro ElectroMechanical Systems". I don't fully understand their application, but using MEMS techniques you could basically manufacture a speaker on a chip instead and other whacky stuff, instead of conventional balanced armatures, dynamic drivers, planars, etc.

And even if you think about manufacturing something like a planar using MEMS, the amt of control you can have in Its construction is on the micrometer scale.

Its honestly a whole new world, and it's probably going to sound like shit at first but I imagine eventually the detail, resolution, and imaging will eclipse e-stats, but in like an IEM form factor.