Dear customer, please note that items Western Digital WD Ultrastar 18TB 3.5' Enterprise HDD SATA 512MB 7200RPM 512E SE NP3 DC HC550 24x7 Server 2.5mil hrs MTBF 5yrs WUH721818ALE6L4 are currently listed as pre-order/on order. You can continue to place a backorder and it will ensure earliest allocation when these products are available. Our team will contact you to notify the expected ETA. Thank you.