Diamond puzzle belongs to a series of 5 puzzles 3D-printed called "priceless". Is that because they are not expensive? Maybe. But they are very great!
I feel there are more and more 3D-printed puzzle. And the reason is easy to guess: they are solid and way easier (and cheaper) to craft than wood and metal puzzles. At the beginning of 3D-printed era I was a bit worries of the quality. And I have changed my mind with the several excellent 3D-printed puzzles.
The priceles puzzles are very clever and very challenging. Diamond is the easiest and I solved it prestly quickly....by luck. The mechanism can be fully visible once solved. I can tell you that there is a lot of rattling things in the puzzle :)
If you ask me whether to buy it or not, I strongly say "yes". They are cheap, challenging, they don't take space and they display nicely. What more do you want?? :)
If you want the solution, you can check Puzzle Master website