bdsamm in pretty sure they're like the number one in chastity belt sales. In light of my investigations to find the best belt manufacturers through the internet suggests so for the recent years even though i can't read a lick of Chinese (but i can identify it from Japanese and i can identify like 50 characters).
zyz ive gone down the political rabbit hole and trust me it's quite deep. Being Australian we're taught about the atrocities that our country did in the past (something that Chinese education does not care much for) and one of the racist strategies we (and usa for their American-Indians) used was to breed out the original land owners by encouraging white partners to intermingle and limiting reproduction among them in attempt to reduce their population.
But yeah for those wondering The recent premium brands of belt manufacturing coming from China is primarily jura's cocoon (sells only that model but has the best measuring tool as far as i know, I'll be receiving one of his belts with next month or two) and the other goes by Twitter handle @SS19125 or 1912, but is otherwise rebranded for western audiences as fetish tools. That last bit is unconfirmed but many people suspect that is the case. The English speaking FT seller advertises a modified variation of ss19125's main design but chains flexibility. The original Chinese manufacturer only speaks Chinese but will use machine translation for correspondences.
Yooka 3d prints nylon belts or something but i highly recommend you avoid going through the English speaking middlewoman (you'll know it's her if you find that their email is registered as a doctor and asks for your Skype details) for many reasons including privacy and the fact she just creates multiple alt accounts to advertise herself while selling her service for quite a steep price (like nearly 1000 usd for the non-international yooka belt model which was like 300 rmb/60 usd, fyi international version has some reinforcements). Yooka themselves is a legitimate manufacturer but accepts crypto weirdly enough and is by no means secure to tampering/cutting as it's not exactly you know, metal. But I've heard good news otherwise.