One of Mussy's RONI series, the Micro RONI is a chassis in which you can mount any pistol with a picatinny rail, thereby turning your handgun into a machinepistol-esque firearm. This RONI is, in essence, a wraparound foregrip for your handgun.
Your pistol is attaches to the RONI using a picatinny rail, meaning that this model will only work if your frame contains this rail. Mussy notes that this model should fit virtually any pistol with a pic rail, although you will likely have the most success with Glock model pistols.
Included in the release package are a few alternate versions of the major parts so that you can customize your Micro RONI as you see fit.