Standard and reference substances after the courier receives them.
Standards, reference substances, and reference substances are used as measurement standards. If there is no problem after sales, they will not be returned or exchanged; if there is any problem, please contact us within 7 days, and the expiration date will not be accepted. Please check the variety and quantity immediately after receiving the standard, reference substance, and reference substance. If the product is found to be damaged, the following documents and items need to be couriered to us: Replacement application form stamped with official seal, a copy of the corresponding outbound list (current page), and damaged products. We will verify after receiving it. After verification, we will resend the goods to you ASAP.
