Wacom launched the Intuos 4 in 2009. These are professional pen tablets.
PTK-840
Intuos4 Large
PTK-640
Intuos4 Medium
PTK-440
Intuos4 Small
PTK-1240
Intuos4 XL
These are still excellent tablets. However, Wacom has dropped support for them in their latest drivers.
For example none of them are listed in the compatibility list for Wacom windows driver version 6.4.4-4:
More here: https://cdn.wacom.com/u/productsupport/drivers/win/professional/releasenotes/Windows_6.4.4-3.html
You can still use these tablets with caveats that come with using older tablets. More here: using older drawing tablets
EyeKooDrawsStuff review of Intuos 4 large Oct 12, 2021
Terry Lee White review of Wacom Intuos 4 May 11, 2009
I also have used the Intuos 4 XL extensively.
This is an extra large tablet. Using a tablet at this size is very different.
I made a video showing what my experience with it is like.
Driver
Wacom's latest drivers have dropped support for the Intuos 4 tablets - except for the Intuos 4 XL.
Pen compatibility
Keep in mind this tablet does not use the more recent pens like Wacom Pro Pen 2.
Availability
It hasn't been produced for years. So, you'll have to find them on eBay. They can range in price from $100 to $500.