This is a very interesting gourd that has been very popular these last few years. It is about 5 inches in diameter, perfectly round, and has almost indestructible thick shell.
Cannonball Gourds are very popular with artisans. For most crafters, they are a more manageable three-dimensional medium than the much larger Basketball Gourd or Kettle Gourd. Cannonball gourds can be crafted into small bowls, lidded containers, or stacked like real "cannon balls"/ snowmen.