This is a mold to make a special kind of rice roll called samgak-gimbap. It’s a specialized tool with only one use but it’s not too expensive, just a few dollars. You can find them in Korean or Japanese grocery stores where they are sometimes they are sold in little kits, and include the gim (seaweed sheets) you need to make samgak-gimbap.
I went to a huge, almost mall-like, store near my house and they didn’t have the wrappers but they had the white shaper sold individually. These little guys are difficult to find, that’s for sure.
I bought this some days ago, it works great! Mine is different, a single box with a small push down presser, it was € 2,=
nice! I will post the samgak kimbap photo you sent me today!
i want to know where i can buy this…
You still can make samgak kimbap without this mold as I showed in the video using plastic wrap. And you can buy it through amazon.com
http://www.amazon.com/Inomata-Sushi-Mold-Triangle/dp/B001QCGGF4/ref=sr_1_2?ie=UTF8&s=home-garden&qid=1245384661&sr=8-2