4x4x6 Fisher Calvins Black Cuboid Puzzle Cube Twisty Toy 6x4x4 Difficulty: Hard, for advance cuboid solver Size: 2.5"x2.5"x3.5" Fully Functional Cuboid, shape shift Not for speed cube, can pop if the cube isn't aligned while you turn Stickers: White/Yellow, Orange/Red, Blue/Green