Yowie and competition in New York City, page-138

Incidentally, the new yowies are slightly smaller than the old ones in physical size, by about 5%. however there is still the same amount of chocolate, it is slightly thicker. The capsule has shrunk but all the old toys still fit into the new capsule so they have just economized on the design. If you compare an old capsule with a new one it is noticeable, also the old capsule and yowies had a bump on their right on their heads which the new ones don't.