Compact games machine with 126 Atari 2600 games included. Looks exactly like the Wonder Boy (even down to the serial number, "WS-11") so no doubt they are the same thing. Seems to be all over Europe.
I like how there's the normal crosspad then like this one huge button on the right there, like you might not be able to find it if it's normal sized or something. System hooks up through normal RF cable (you don't need one of those "Game/TV" switches like the OG) so it should work on modern TVs without a problem. It's a PAL system but NTSC versions are availible.
You can find these things on Ebay pretty cheap any given day of the week.