It's an exclusive, reserve order only, Miku bento set (lunch box). It was only released this month, from the 8th to the 12th, at select Family Marts in Japan. I think it was released to help promote this song:
All the food has been eaten, but the box and chopsticks have only been used once then washed clean. I also have the "special" pink plastic bag, unused.
Would you be interested in buying this item? How much would you pay for it? ;D