After a long search I found the Razer Sphex and was immediately impressed by the extreme "flatness".
It is about as thick as a sheet of paper (100g).
The surface is hard and structured.
The gliding (Logitech G5) are super. When the mouse easily glides anschubst far above the pad.
The thing that sticks now for over a year on meiem table, for hours UT, C & C, SC, WOW, etc. has fallen Sessions leave and is keeping perfectly still.
During the day it is exposed to direct sunlight, and it has neither warped nor is faded.
Peeled and stuck again I have been three times.
When sticking, it is important to ensure that the table surface is absolutely clean. Top wipe the table with a damp, lint-free ink.
Even the smallest crumbs under the pad prevents a perfect sliding of the mouse.
My Conclusion:
Those looking for a flat Gaming Pad for permanent use on the desk and not constantly changing the position of the pad, is well advised with the Razer Sphex.