Model: Fujitsu Lifebook T4010D
CPU: Intel Celeron M (Dothan/Banias, 32-bit) @ 1.8 GHz
(but usually runs at the minimum 0.6 GHz to save power)
RAM: 512 MB originally (upgraded to 1 GB)
HDD: 60 GB originally
Screen: 12.1", 1024x768
OS: Debian 11 i586 (originally XP Tablet PC Edition)
The Lifebook is a nice compact device for miscellaneous linuxing, mostly acting as an SSH terminal. Its battery isn't as good as it used to be (though still lasts over an hour), so nowadays it runs at 0.6 GHz in the Linux "powersave" mode most of the time.
It has a pen tablet screen. You can write on it with the included pen/stylus (or at least use it to control the mouse pointer as far as Linux goes), and you can even twist the LCD around so that it becomes a very thick tablet. The digitizer layer also gives the image a nice fuzzy look which makes text pleasant to read.