Authentic, screen-used prop from the LOST show.
The Dharma cafeteria with adjacent kitchen is located in a large building, in the southern cluster of the barracks.
The Dharma Initiative DHARMA O'S cereal box is seen among others in the background in a scene in 1977, where
Kate,
Hurley and
Jack are sitting together inside the cafeteria.
As seen in S5E10 - He's Our You.
The box is sealed and even contains some kind of filling material, the size is 2.8 x 1.8 x 4.7 inches.
I purchased this prop along with some more items from a LOST Film Crew member.