As per Amazon, there is no required maximum or minimum quantity of products you can send to them for fulfillment since fulfillment fees are charged per order at the time of the sale.
Because you will be shipping your products to Amazon, it might be best to send in a group rather than individually to be more efficient and to save on shipping costs as well. When your customers place orders, Amazon will take care of packing and shipping the products to your buyers.
If you plan on send your inventory one-by-one then might as well ship your products yourself, rather than sending them to Amazon.
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