4x4x6 Calvins Puzzle Transparent Blue Cuboid DIY Stickers Cube Twisty Toy Ice Blue 6x4x4 Limited Transparent Version Diffculty: Hard, for advance cuboid solver Fully Functional Cuboid, Shape Shift Not for speed cube, can pop if the cube isn't aligned while you turn DIY Stickers Set: Black/Yellow, Orange/Red, Blue/Green