Guo Jia Diamond. A simple 3x3 shape mod made by the Chinese company Guo Jia, who produces many more twisty puzzles.

Visually very appealing, due to its reflective stickers and its truncated hexagonal dipyramid shape, the Guo Jia Diamond has a pretty decent quality for its price ($6 USD). Probably not for speedsolving but, it's almost there.

Also available in red, you can purchase one at Popbuying. This one came from there and I can tell you that they are trustworthy. Took around two weeks to arrive.

You can also see a video of the puzzle and its shape-shifting abilities here and judge it by yourself.