Uxcell components?

[bitman]

Hey - I'm really not sure this is a good topic for "Beginners" but since that's what I am, I'll post here.
On Amazon, AliExpress and a ton of other consumer shopping sites, if you search for basic electronic components like connectors, there's a very good chance you'll get some links with Uxcell stuff. They're usually priced reasonable for low quantity purchases. My question is how reliable these components are? I'm asking because I cannot find data sheets for any of the items, not even on Uxcell's own site. And I don't find their products on Mouser or Digikey.

Here's an example:

http://www.uxcell.com/20pcs-green-hg129508-terminals-pcb-mount-508mm-pitch-screw-terminal-barrier-blocks-300v-20a-p-671011.html
https://www.aliexpress.com/item/20-Pcs-HG129-5-08-2Position-2Pin-5-08mm-Screw-Terminal-Barrier-Blocks-300V-20A/32341269123.html
https://www.amazon.com/uxcell-HG129-5-08-5-08mm-Terminal-Barrier/dp/B00VG9BHB0

When I look at similar screw terminals on Digikey, their ratings are only around 15A but I also have data-sheets that gives me complete dimensions and predicted performance etc. I feel like I'm missing something? Why would Uxcell not have data-sheets? Are their claims exaggerated or untested for the rating?

Note, I've gotten a good deal of Uxcell in the past, and I've been happy with what I got. Not exactly the highest quality but for my peddling with electronics it's been good enough. But I'm getting to the point where I'm starting to doubt that I've made good decisions since I cannot find any materials covering the products they've offered. And since it's all over the web, with pretty much the same descriptions etc. I feel like I've been duped .... ?

[ataradov]

A few things I've bought from Uxcell via Amazon were clearly not unique items. I assumed that Uxcell is just a reseller, not a manufacturer (even of white label stuff).  They are not better than any random seller on eBay or AliExpress as far as I can tell.