Let me preface this by saying that I am a beginner. Those more experienced may feel that the keyboard I talk about below is pure garbage, and not suitable, even for practicing. That may be, but for now, my needs are simple, and their are few choices for an 88-key travel keyboard.
I'm in the Merchant Marine, so when I go to work, I'm away from home for months at a time. I wanted a keyboard that I could take with me for practicing when I'm at sea. It had to be something that I could carry on an airplane, as I don't like to check luggage. The keyboard will count as my "personal item", in addition to my carry on bag.
My research found three 88-key keyboards that either folded or split into pieces, priced from $100 to $200. There were a few other such keyboards that cost much more, but they may or may not actually be available (one was a Kickstarter). I didn't consider short keyboards under 61-keys.
After searching online and watching YT videos, I decided to purchase the NikoMaku Portable Piano Keyboard from Amazon.https://www.amazon.com/dp/B08L7RX2P1/
This is actually a rebadged Bora BX-20. The box is actually labeled "BX-20".https://borapiano.com/products/bx-20-foldable-piano--travel-piano-115
You can buy one for a bit less on Bangood, if you don't mind waiting weeks to get it from China. I thought that the ability to have it in two days, and to return it easily to Amazon if necessary, was worth a bit more.
Amazon only had the white keyboard. If you want the black one, you'll have to get it from China.
The product video shows that the mating halves use pogo pin connectors. The keyboard I received used a reinforced ribbon cable. While I'm sure the ribbon cable was done as a cost savings, I think that this is the better solution, from a reliability standpoint.
As for instrument sounds, don't even bother using the built-in 2W speakers. Headphones sound much better. No, this is not going to sound like an expensive keyboard, but for practice while travelling, it is adequate.
The keys are velocity sensitive, but feel a bit heavy.
The zippered case is padded, but I added 1/2 inches of dense foam on the top, botton, and folding side (not using the included protective plastic end cover). The case still zippers closed, but it is a tight fit, especially with the music stand included.
Keyboard, music stand, bag = 10 lb, 8 oz. Add 5 oz for pedal and charger. The USB charger looks to be like the very cheap ones that you get in the dollar store. I wouldn't trust it, but since I have several good USB chargers, that's not an issue.
I did not test the USB or Bluetooth MIDI feature. I expect that it works, but I won't be using it.
I could wish for something better, but compared to the other folding keyboards that I was able to find in this price range, I think this one is the best of the bunch.
If anyone knows of a better keyboard that folds, please let me know. If it isn't too expensive, I can still return this one.