Game collectors have by dying to play their original Sega Game Gear, Master System, and Master System Card games in HD. The Hyperkin 3-in-1 adapter easily inserts into the Genesis slot on the RetroN 5 and adds this functionality. Play your favorite games with enhanced resolution, improved interpolated sound, screenshot capture, and the ability to have on-the-fly save states. 
Hyperkin: http://goo.gl/YDAu6k