QNAP Advanced Replacement Service (QARS) is an optional service to expedite hardware replacement. QNAP products are designed and 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.