Reddit reviews Sega Game Gear Master System Converter
We found 3 Reddit comments about Sega Game Gear Master System Converter. Here are the top ones, ranked by their Reddit score.
An adapter for the Sega Game Gear allowed for Sega Master System cartridges to be plugged in and played on the Game Gear.
The game gear was practically a portable Master System. There es even a converter that let you play MS games on the GG.
http://www.amazon.com/Sega-Game-Gear-Master-System-Converter/dp/B00002SSZO
You're correct. Look here
It looks like they still make Master System Cartridge Adapters.