Small dusty box of some sort

It weighs 2 pounds and costs $20. It can be found in Fallout 1, one place being a desk in Junktown. This item has no actual purpose beyond being sellable, though its weight makes it impractical for even that.

It also can be found in Fallout 2. One in the fridge where the Slags live and another in the fridge under the Malamute Saloon.