The Master System Player from RetroSix is a brand new device made in memory of the Master Gear Converter; it is simplistic device which fits into the Game Gear's cartridge slot, which in turn allows for western-style Master System cartridges to be placed inside and run on the Game Gear.

Similar in nature to the Power Base Converter for the Sega Mega Drive. The Game Gear is essentially an upgraded Master System and thus has no trouble playing Master System games, however is unable to offer any other advantages such as FM Sound offered by the FM Sound Unit. It also cannot run Sega Card natively, though could in theory do when armed with a Card Catcher and a Master System Region Converter.