definiens: shall mean that theProduct shall perform in accordance with its specifications and manuals, and be in physical condition and functionality equalto or better than that of the Product being replaced . In addition, NxStage shall use all commercially reasonable efforts toensure that replacement Products provided to Customer or any Authorized Customer Location in connection with a serviceswap shall have an average days in service approximately equal to or less than the estimated days in service of the Productreturned by Customer in connection with a service swap hereunderPeriodically, NxStage may elect to diagnose Product servicing issues remotely, through data analysis or phone interviews . IfProduct is returned at the insistence of Customer, an Authorized Customer Location or any of their respective patients, contrary to the recommendation of NxStage, and it is subsequently determined in the reasonable discretion of NxStage thatsuch Product was in Good Working Order, Customer shall reimburse NxStage for the related costs of such return