I have one that's several years old, and I haven't used it as much as I thought, but it has worked fine on a couple of occasions.

The "packed" - "unpacked" thing may refer to the cardboard box it comes in, which is tight fitting and would probably add that weight and those dimensions. I keep it in that box for storage.

I put a tape hinge and a magnetic "latch" on the battery compartment door (replacing the screws) so I could more easily remove & replace the six or eight flashlight batteries. I was afraid they'd corrode between uses. It is a very lightweight little unit that puts out a good amount of sound.