Very simple kind of project in Korea.
It is just for fun and want to make a world's smallest MSX with Keyboard.
You could imagine the size with the gradius cartridge.
This is Gradius MSX cartridge. Not imagine it is MVS cartridge. 
This has very simple speaker amp inside but a little bit noisy..
It is using LM386 for speaker amp. But anyways it has sound function inside.
(Can turn it off with dip switch.)
Cartridge is closed automatically with torsion spring.
Size compare with a box of cigarette. But I cannot image the size because I'm not a smoker.
Cause I compared with my hand.. Big hand.. :)
Just compare with Zemmix Neo. A little bit smaller than Zemmix Neo. (about 1 cm smaller)
sorry 