No. IV.2.7 - Writings in confirmation
If a writing which is sent within a reasonable time after the conclusion of the contract and which purports to be a confirmation of the contract contains additional or different terms, such terms become part of the contract, unless they materially alter the contract or the recipient objects to the discrepancy without undue delay.
Principles / Restatements
1. Contractual Clause Expressly Excluding Writings in Confirmation
Sales & Purchase Contract
Purchase Order for Customized Goods
Unless expressly accepted in writing by Purchaser, additional or differing terms or conditions proposed by Seller or included in Seller's acknowledgment are rejected by Purchaser and have no effect. - (International Contracting: Law and Practice - Larry A. DiMatteo - 6.05 A - S. 202).