The four main warehouses can be broken into two subcategories, sellable and unsellable.
Sellable Warehouses – “Sellable Warehouses” track “Physical Inventory” and use that as part of the “Available Quantity” calculation being synchronized to your sales channels.
Nonsellable Warehouses – “Nonsellable Warehouses” track “Physical Inventory,” but do not add that as part of the “Available Quantity” calculation. “Nonsellable Warehouses” are mainly used to track raw materials, returns/damaged inventory, or FBA Removals before getting them back out into circulation.