Western Digital · Enterprise
WUH721818ALE6L4
Ultrastar DC HC550 18TB
SATA 6 Gb/s · 3.5-inch
Exact Amazon US product
$529.00
View on Amazon US ↗Used / renewed listing · ASIN B09RYLD7GL
Price as of Sep 12, 2026 04:47 UTC
The Western Digital WUH721818ALE6L4 is a 18TB Ultrastar DC HC550 hard drive for server and enterprise storage, using SATA 6 Gb/s in a 3.5-inch form factor.
Manufacturer specifications
| Model number | WUH721818ALE6L4 |
|---|---|
| Nominal capacity | 18 TB · 18000 GB |
| RPM | 7200 |
| Interface | SATA 6 Gb/s |
| Cache (MB) | 512 |
| Form factor | 3.5-inch |
| Sector format | 512e |
| Drive construction | Helium |
| Power Disable Pin 3 | Not supported (legacy configuration) |
Source: Western Digital Ultrastar DC HC550 datasheet, pages 2. Reviewed 2026-09-07. Published specifications, not our benchmark results.
What the specifications mean
Before ordering
Match WUH721818ALE6L4, 18TB and SATA 6 Gb/s against the selected offer. Check your system’s exact-model compatibility list and the seller’s warranty and return terms.
Amazon US listings
Exact model matches on Amazon.com. A verified ASIN identifies the product; it does not guarantee current stock. Check the selected variant, condition and seller.
Amazon US · ASIN B09RYLD7GL
$529.00 · as of Sep 12, 2026 04:47 UTC
Amazon US · ASIN B09NP4Y2JC
$661.00 · as of Sep 12, 2026 04:47 UTC
Same-capacity alternatives with Amazon US links
These models share the drive type, interface class and capacity. Compare their specifications and your system requirements before choosing a replacement.
Seagate · IronWolf Pro
ST18000NE000
18TB · SATA 6 Gb/s · CMR
Compare with WUH721818ALE6L4 →View on Amazon US ↗ASIN B0CZM957F3 · Check price and conditionToshiba · MG09
MG09ACA18TE
18TB · SATA 6 Gb/s
Compare with WUH721818ALE6L4 →View on Amazon US ↗ASIN B093Z5LFWD · Check price and conditionSeagate · Exos X18
ST18000NM000J
18TB · SATA 6 Gb/s
Compare with WUH721818ALE6L4 →View on Amazon US ↗ASIN B08JV6PP9B · Check price and conditionWUH721818ALE6L4 questions answered
What connection does WUH721818ALE6L4 need?
WUH721818ALE6L4 uses SATA 6 Gb/s and a 3.5-inch form factor. Match both with the computer, controller or enclosure. An M.2 slot, 2.5-inch bay and 3.5-inch bay are not interchangeable.
How much usable space does WUH721818ALE6L4 provide?
Its nominal capacity is 18000 GB, approximately 16763.8 GiB before formatting. The filesystem, reserved space and any RAID redundancy reduce usable capacity further.