Here are 4 "Sound Flash" yoyos!
These are an even more rare sight because they are all still mint in the package. These would likely flash tiny red lights inside & make some kind of sound while they were spinning on their string. Each package is the same with waving Tails & jumping Sonic along with the Segasonic banner & 2 illustrations of lighting up yoyos. The package is very busy with dots & lines to indicate action. Each yoyo is quite different. The first is green with a yellow twirl shape & Sonic with Tails standing. The next has the star-ring with banner & Sonic & Tails inside like at the game title screen. The next yoyo is reddish with a star ring and has only Tails on it as a portrait. (Though it is the 'big nose' stock art of him) The last yoyo has spinning Sonic with a 'speed lines' sort of border in red & yellow. This is a nice selection of yoyos from the early 1990s.