The Arcade Gamer Portable, also known as the AtGames Gear, is a Sega Master System and Sega Game Gear console on a chip. It was manufactured by AtGames, though has been distributed across the world by various companies, including Blaze Europe (as the BlazeGear).
The console contains 30 built-in Sega Game Gear and Master System games. It uses emulation software to run the games, and does not have a traditional cartridge slot. It can also be connected to a television to play the games on a large screen instead of the built-in LCD screen, however it will only output a PAL signal.
AtGames would also release the Arcade Portable, which offers a similar service for Sega Mega Drive games.