Graham Russell on Twitter: "The Sufami Turbo was an effort by Bandai to sell games more cheaply by offering a larger base cart and small-cart inserts that contained the actual game data.
Sufami Turbo & Ultra Battle Ultraman Densetsu SFC (B) – Retro Games Japan
Snes Central: Sufami Turbo
Bandai Sufami Turbo Games A to Z - Super Famicom Add-On - Launchbox & Hyperspin Arcade - YouTube