This is the second version of the Quick-Release Picatinny Rail Mount. The V2 is about 40 percent smaller by volume then the V1. The quick-release allows for easy changing of accessories or adjustment on the fly. This thing is fully printed and print it in place, no fancy assembly or extra parts needed. The model also has a picatinny rail and holes strategically placed to let you mount all kinds of stuff like sights, grips, and whatever else you want.