4. PriceExcept as otherwise provided in this VPSA, pricing for Products shall be as listed on Exhibit A. In the event, subject to RHEM’s approval, CUSTOMER replaces the slurries with other type of slurries of RHEM CMP, or CUSTOMER needs new type of slurries from RHEM other than these listed in Exhibit A, Exhibit A shall be revised accordingly while the price for the types of slurries which are unchanged shall keep the same.In the event that significant raw material or energy price fluctuations beyond RHEM CMP's control occur such that continued performance under this VPSA would cause an unreasonable economic burden on RHEM CMP ("Hardship"), RHEM CMP may provide CUSTOMER with written notice of such Hardship. Within thirty (30) days of such notice, the Parties agree to confer to negotiate in good faith such modifications that will alleviate the Hardship in a manner that will be equitable to both parties. If no agreement on such modifications to the VPSA can be achieved, RHEM CMP, in its sole discretion, reserves the right to alter the billing price of the product(s) under Hardship condition or impose a surcharge which shall be immediately effective.