Here is a simple ball featuring Sonic 3 theme. This is a medium-size smooth-surface ball often called a "Play Ball" which is made of semi-soft rubber and is full of air. It can be used in outdoor games and is fairly bouncy. Despite being a rather simple item, it has good design and is colorful.

Sonic is giving the "3" fingers on the front, while Knuckles is jumping in looking rather irritated. They're both in front of a large 3, which has bolts for details. The back, curiously enough is checkered much like the special stage which takes place on the surface of a large sphere! That portion of the design is actually rather clever. The logo on the back is also in fine form, looking stylish and shiny. This ball is from 1994, and there should exist another, with a different design.