Here's the link to the 15.6 Pro:
https://www.photodon.com/p/3358-01.html
If you want to look at the others; go back to the main page and click "Find Your Device".
It may be confusing at first, because they have a lot of options and they're named odd.
If you want a protector just like the ones XP-Pen sells; buy the MXH: 25%. It has anti-glare, but it's not super slick like glass and has a nice matte finish. I use this one a lot.
Or I also buy MXO which is a completely clear protector. It's sort of like glass.
If you want a heavy duty protector which can take a big beating; buy 9HO.
So in short:
To see their full list: https://www.photodon.com/Film-Comparison-Print.pdf
For the tablet stand; I bought: https://www.amazon.com/Parblo-Universal-Adjustable-Compatible-Comfortable/dp/B07B2FKTXP
I have the 16" and used these for both of them: