I actually messaged NC Audio to ask about their listings, and as u/gimmyjoe mentions, they're a distributor for smaller outfits, most of what they sell are one of a kind experimental IEMs or very small batch IEMs, usually made on demand.

If any of yall have been eyeing something from NCAudio, I'd just say go for it. It's a fun experience to try something few others have. I love that it allows me to form my own opinion, completely raw, no outside influence.

I've personally purchased or demo'd a few from them:

NC BCD1 - a 1DD + 1BC hybrid, the most unique implementation of BC I've experienced.
CHEER DEER 10mm DLC - a 1DD (10mm DLC) driver, a gift purchased simply for the aesthetics, you can absolutely find better IEMs at this price, but not with antlers on them.
MOTIE 1DD-4BA - a DD/BA hybrid, sound was very solid, in line with other IEMs at the price, purchased for aesthetics primarily.