QNAP Advanced Replacement Service (QARS) is an optional service to expedite hardware replacement. QNAP products are designed & manufactured with high quality components to provide excellent reliability. For additional protection, QNAP offers advanced replacement plan for customers who want to minimize the amount of time without a QNAP unit when seeking service under QNAP's warranty. QNAP will ship you a replacement unit in advance before having to return your replaced NAS. The advanced replacement plan is a great option for any customer to have.