definiens: means, collectively, for any applicable period, ( a ) the aggregate amount collected by the Purchaser and its Affiliates inconnection with the license or sale of Royalty Products by or through the Purchaser and its Affiliates in the United States ( exclusive of salesmade -4 - by the Purchaser to its Affiliates for resale but inclusive of sales made through sales agents and licensees, less ( b ) freight, duties, sales, use, excise, value added, Medical Device Excise Tax, and other similar taxes attributable to such sales ( except for taxes based upon the net incomeof the Purchaser and its Affiliates ) and discounts, rebates, chargebacks, customer returns and allowances given or taken, as appropriate, related to such sales of Royalty Products by the Purchaser and its Affiliates . Net Sales shall be calculated using the internal system of thePurchaser and its Affiliates used to calculate and report net sales for all its products