In your company you may sell packs made up of multiples of a product or variant; for example a 12 pack of beer.
Your product is a certain type of beer that comes in bottles; Beer XYZ.
You wish to sell Beer XYZ both as individual bottles and in packs of 12 bottles.
This means that you will need to set up and individual bottle of beer as a variant.
After which you, add the pack of 12 as a pack size within your product.
When an order for a pack of 12 is made the stock level of the variant for the individual bottle of beer will then fall by 12.
With TradeGecko's pack size functionality you can easily create pack sizes that are made of different quantities of stock items.