Item net weight - best practice sought

Let’s say we have an item which is Belt. this belt is packed individually in a small plastic box and shipped in a carton box containing 144 of those belts

how would you define the net weight in item?

  • a) The weight of the naked belt or
  • b) weight of one belt packaged in it’s individual plastic box

I tend to option b) cause that would give me more precise numbers for shipment purpose