The dimensions (about 1.77cm/0.7in diameter) are accurate, but it still seems smaller than I expected. The shape and details aren't very sharp at this size, and the material itself is a bit fuzzy. The numbers cannot be seen from across a table, so you'll have to get close to it to check the numbers.
It seems to be fairly balanced, and perfectly functional if you don't mind squinting. I intended for this to be a 40th birthday gift for my DM, but it just looks tiny, cheap, and unfinished compared to your average plastic d20.
My only problems with this die are aesthetic; If you just want to roll a number between 1 and 40 then this is perfect. But if you want a cool and unique die to show off to your friends then I recommend looking elsewhere.