Micron shall have the right to have an independent Third Party auditor audit [***], upon reasonable advance written notice, during normal business hours and on a confidential basis subject to an obligation of confidentiality, all records and accounts of NTC relevant to the calculation of Micron IP Royalties in the [***] period immediately preceding the date of the audit; provided, however , NTC shall not be obligated to provide any records and book of accounts existing prior to the Exercise Date. NTC shall, for at least a period of [***] from the date of their creation, keep complete and accurate records and books of accounts concerning all transactions relevant to calculation of Micron IP Royalties in sufficient detail to enable a complete and detailed audit to be conducted. In the event any such audit determines that Micron IP Royalties have been underpaid by more than [***] U.S. dollars ($[***] USD) in any one [***], NTC shall promptly pay Micron such underpayment amount, together with interest, and reimburse Micron for its reasonable costs and expenses of the audit.