V-Cube 6 to the internal mechanism, thus making the puzzle more durable. The V-Cube 6b, which has the same "pillowed" shape as the V-Cube 7, was introduced later. There are 8 corners, 48 edges and 96 centers. Any permutation of the corners is possible, including odd permutations. Seven of the corners can be independently rotated, and the orientation of the eighth depends on the other seven, giving 8!×3 combinations. There are 96 centers, consisting of four sets of 24 pieces each. Within each set there are four centers of each color. Centers from one set cannot be exchanged with those from another
Rubik's Cube into it to form the assembled puzzle. Each of the six centre pieces pivots on a screw (fastener) held by the centre piece, a "3D cross". A spring between each screw head and its corresponding piece tensions the piece inward, so that collectively, the whole assembly remains compact, but can still be easily manipulated. The screw can be tightened or loosened to change the "feel" of the Cube. Newer official Rubik's brand cubes have rivets instead of screws and cannot be adjusted. The Cube can be taken apart without much difficulty, typically by rotating the top layer by 45° and