Use this field to indicate the number of units included in the item you are offering for sale, such that each unit is packaged for individual sale. Use this field to indicate the number of discrete items included in the item you are offering for sale, such that each item is not packaged for individual sale. For example, if you are selling a case of 10 packages of socks, and each package contains 3 pairs of socks, the case would have ItemPackageQuantity = 10 and NumberOfItems = 30.