I used to have one of these back in the day, when I got my original style GBA. It was a snap on cover that went on the back side of the system to make it feel more like a console controller. It did not have any speakers, rumble packs, anything special, no lights, it was just all plastic. What was it called? I'm trying to find it because I plan on setting a world record in a GB game, and I need a link so I can ask a Twin Galaxies referee directly whether it is allowed
More specifically, I remember the one I had was in dark purple, and it was strikingly similar to this for the SP: http://vpgames.com/p-6075-gba-sp-handy-dual-grip.aspx

More specifically, I remember the one I had was in dark purple, and it was strikingly similar to this for the SP: http://vpgames.com/p-6075-gba-sp-handy-dual-grip.aspx