The Twisted-8 puzzle is an eight sided solid with ten axes of rotation. This shape is technically known as a tetragonal trapezohedron, but I think of it as a twisted octahedron. The two tips of the puzzle turn in 45 degree increments, and the eight edges around the equator turn in 180 degree increments. Twisted-8 utilizes a unique mechanism, but due to the large number of small parts and sharp angles it is not suited for speed solving. Take care to align slices completely before turning.
The puzzle comes as a DIY kit of parts, and you will need to supply your own stickers. The sticker template is available on the instructions forum
I recommend that you purchase the puzzle in "Black Strong & Flexible". It costs a bit more than the white material, but it's worth it since the finished puzzle will look and work better. All of the parts snap together, so no additional screws, springs, or other hardware is required. I have also made an assembly video
so that you can see exactly how to put the puzzle together.