Works perfectly in an original Model 1 or 2 Sega Genesis, Nomad, or Mega Drive system. Mini Gen, Retron 3, Retro Trio, Genesis 3 and RetroAD systems also work perfectly. ATGames systems will NOT work. This means the Classic, Flashback, etc.Retron 5 WILL NOT WORK - it is an Android emulator, not hardware. 200 in 1, All Classic and Some Rare Games Perfect Collectors Item with so many Classic Games NOT OEM item, but nothing different from the official function, even better than the original. The built-in games are all US versions.