Roller Controller with Slither Cartridge

Coleco's trackball for the ColecoVision, sold with a conversion of the arcade game Slither - a game built around a trackball, so the pairing makes the case for the hardware.

How it connects

• The Roller Controller plugs into the console's controller ports, and the ordinary hand controllers then plug into the trackball unit itself.
• So it adds to the controllers rather than replacing them, which is how a game can use the ball for aiming and the keypad for everything else.

What else uses it

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

It is a large, heavy unit by the standards of home controllers of the period, which is part of why surviving examples are usually in reasonable condition.