I've been using these for the last 8 years, and the smaller 500ml version. Some of my originals are still in use, I imported the first ones from Germany when the Euro was worth 0.56 £GBP. They're a lot more available here in the UK now, and also available on AliExpress. I love them, it's so easy to just top up the water every day. They do need regular removal for cleaning, and you need to watch out for loose fluff accumulating round the nipple especially in breeding cages. But easy enough to clean, and they come apart. The nipple section can also be replaced if you can find somewhere that stocks them. You may also need to soak the nipple section in vinegar occasionally as limescale can build up inside if you live in a hard water area, making them prone to leak.
I've found the black part on alibaba, but no one ever says who they used, just "get an interpreter, use a gift card, check details." Ugh, just name the seller!
Haven't checked aliexpress.
Amazon sold a different version of that black part, but it leaked immediately from the O ring.