What are the dimensions of a cube in EyeWire?

Question from chat would be good to go in FAQ.

Answer from Jinseop:

one pixel corresponds to 16nm (nano meter) x 16nm in x-y direction and 22nm in z direction. z direction is where the tissue was cut. 

256x16 = 4.1 um (micro meter)
256x22 = 5.6 um

updated on the wiki