The ShengShou Crazy 4x4 V2 is a 4x4 with rings in the middle of each face. These rings (consisting of 12 pieces each) do not turn with the faces of the puzzle. That makes this puzzle a bit more difficult than a standard 4x4. And even more difficult than the ShengShou Crazy 4x4 V1. Give it a try if you think you can tackle this complicated cube!