Roller Controller with Slither Cartridge (EU)

The European issue of Coleco's trackball, packed with the arcade conversion Slither, distributed by CBS Electronics.

How it connects

• The Roller Controller plugs into the console's controller ports, and the hand controllers then plug into the trackball unit itself - so it adds to the controls rather than replacing them.
• Slither was built around a trackball, which is why the two were sold together.

What else uses it

• Victory, Omega Race and WarGames, and Atarisoft's Centipede - an arcade game that used a trackball originally.