This die has 36 sides and is numbered 1 to 36. 40mm diameter.
Also since rolling 2 D6 dice have 36 possible results, this die also shows all 36 results of rolling 2D6 at the same time. The pips above the number show the result of the first D6 and the pips under the number show the result of the 2nd D6.
You can even make interesting tables using all 3 numbers. Possible RPG table shown in the images.
Note: As with most dice with many sides, it is best to use this die with a dice tray.