This add-on allows a store owner to set a stock value for each variant of a product. For example, if you have three sizes, large, medium and small, this module will allow you to keep track of all the different quantities. It will work for a virtually unlimited number of amount of attribute combinations. For example, if you offered cotton or polyester shirts in green, red or blue and small medium or large sizes, this add-on would allow you to enter and maintain a separate stock level for each of the 18 possible combinations.
This mod involves editing / replacing several core files as well as updating the database.