A.) Truncated cone, if we're going to be semantic about things.
2.) Said truncated cone had the measurements clearly listed before you could even see it, and in addition, was explicitly called out as larger than a potion bottle. The example was intended as a reference point, something most people would be familiar with even if they do not use it, to help visualize how small a potion bottle would be, since it is even smaller than that (which, again, us why the measurements were clearly called out in advance).