A shipping container has both a weight limit and a volume limit, and cargo reaches one of them first. Laboratory plasticware, PPE and empty vials are all light relative to their bulk, so they reach the volume limit with the weight limit nowhere in sight.

That inverts the usual purchasing instinct. On dense goods, negotiating unit price is the main lever on landed cost; on volume cargo, how the goods are packed and what else is in the container matters at least as much.

Two practical consequences follow. First, mix dense items into the load where the order allows it, because the weight capacity is otherwise wasted. Second, choose bulk cartons over presentation cartons wherever the market permits, because presentation packaging can easily take half again the volume for the same number of units.

Plan the order as a load rather than as a list, and ask for a loading plan with the quotation. On this kind of cargo the loading plan moves the landed cost more than a price negotiation usually does.