Caramel Box is the IPP34 design competition entry from Yasuhiro Hashimoto and Mineyuki Uyematsu (MINE). It also came in top 10 for most votes garnered for the Puzzlers' Award.
While I am not too familiar with Hashimoto-san, I enjoy MINE's designs and have a couple of his puzzles including the T4-II and T4-III. His packing puzzles usually do not have a lot of pieces (no more than 4), but yet provides a nice (and not overly difficult) challenge that is just right. Caramel Box is one such puzzle, although it did stump me a fair bit longer than the previous two.
There are two challenges here... to get two sets of various irregular shaped pieces flat into the metal box. Usually not a problem since its only a 3x3x2 but in this case the opening of the box has an obstruction in one corner, making the solve more difficult than one might imagine.
Packing the pieces would require you to figure out the shape the pieces must form to fit inside the box...pretty straight forward, although the wrong shape would mean getting stuck along the way. And then figuring out how to insert the pieces into the box...which is not so straight forward. I found the second challenge easier than the first, which is a bit odd since the first is usually the easier of the two.
Quality and build is excellent. The two sets of wood pieces are made from Teak and Poa Rosa respectively and the box is thick walled steel. A really solid mix of metal and wood.
Overall a really nice puzzle of high quality. I believe there are still some copies available for sale. You can purchase the Caramel Box and other puzzles via MINE's website. Yes, he does ship overseas.