In making a decision between purchasing a Medium Duty Freezer spacer (1,800 lb capacity) and a Heavy Duty Freezer Spacer (3,600 lb capacity) always remember that a freezer spacer does not get placed between a pallet and the base of the bottom layer of the load. (The wood or plastic pallets usually have spacing to provide airflow.) This means that the bottom layer’s weight should not be counted when determining how much weight will ultimately be resting on a freezer spacer. For example, if the load you are freezing and/or transporting is 2000 lbs and your bottom layer weighs 300 lbs then you can determine that the Medium Duty Freezer Spacers will be more than capable of handling the weight of the load. To be certain for your specific application we would recommend purchasing a small quantity of Medium Duty Freezer Spacers and Heavy Duty Freezer Spacers and test them side by side. Your decision ultimately rests on whether either of the freezer spacers collapses under pressure because if it does then airflow is impeded.