This is a grip for the emulation handheld: BatleXP G350. 

Update: I adjusted tolerances for the G350 body as well as the sd card openings so the fit is still snug but not too difficult to remove.

The grip snaps onto the BatleXP G350 by fitting to one of the ribs on the back of the console, and the two bumps inside line up with the screw holes to keep the console from wobbling around. There are two thumb holes at the bottom so you can push the console back out without forcing anything. Both SD card slots stay accessible while the grip is on. The openings are small, so you will need something like a pen tip or a tiny flathead to pop the cards out. The whole setup is meant to stay solid and feel good in the hand, while still letting you reach what you need.