Meet the Coolboy, the latest to come out of the console clone factories of Asia. This particular machine is about the size of a Game Boy Micro, with a 2.4 inch screen. This handheld also has the ability to output AV so you can play your pirated games on the big screen.
Speaking of games, the cartridge looks to be about the same size as a standard Game Boy Advance cart. Console emulates the 8-bit NES (no surprise there) as well as 16-bit Sega Genesis games. The only way to obtain games for this console short of using your own flash carts is to buy them in dodgy "120-in-1" game carts sold alongside the console, which show the usual lists of pirated games along the back label with the names changed to protect the innocent.
The Coolboy retails for a measly $36 USD and is currently available online via the usual HK import sites.