Used
$25.86/TB
18TBSAS
WD Ultrastar WUH721818AL4200 18TB SAS 12Gb/s 7200RPM HDD Tested 2 Years Warranty
$465.46
In stockWestern DigitalSAS18TB3.5 in
Western Digital Ultrastar DC HC550 18TB SAS (WUH721818AL4200)Specs, test results and price
14 in stock from $465.46 · 19 units tested in-house
In stock now (1)
About the WUH721818AL4200
The Western Digital Ultrastar DC HC550 (WUH721818AL4200) is an 18TB enterprise hard drive built on a SAS 12Gb/s interface in a 3.5 inch form factor, spinning at 7,200 rpm. This family is designed for high capacity storage roles such as bulk data retention, backup targets, and nearline storage in servers and storage arrays that support SAS drives.
Every unit in this listing has been tested individually. All 19 drives tested passed, with recorded power-on hours ranging from 12,762 to 12,882 and a median of 12,784 hours, placing them in the Light Use tier (500 to 20,000 hours). Each drive underwent a sequential and random read/write benchmark, a full extended self-test across the entire surface, a power-on hours cross-check against an independent on-drive log, a NIST 800-88 sanitize with read-back verification, and a SMART health read covering reallocated, pending, and uncorrectable sectors.
Median benchmark results across the tested units show sequential read speeds of 269 MB/s and sequential write speeds of 143 MB/s, consistent with this drive class. These figures and the pass results reflect the condition of the units at the time of testing.
Specifications
| Brand | Western Digital |
|---|---|
| Part number | WUH721818AL4200 |
| Type | Hard drive |
| Capacity | 18TB |
| Interface | SAS 12Gb/s |
| Form factor | 3.5 in |
| Rotational speed | 7,200 rpm |
Tested units
- Units tested
- 19
- Pass rate
- 100% (19 of 19)
- Units sold
- 5
- Power-on hours, median
- 12,784 h
- Power-on hours, range
- 12,762 to 12,882 h
- First tested
- Oct 16, 2026
- Last tested
- Nov 1, 2026
- Sequential read, median
- 269 MB/s
- Sequential write, median
- 143 MB/s
Every unit of this model we have handled, from our test database. What we test
Hours distribution
- Light Use under 20,000 hrs19 units · 100%
Units by usage tier, from their SMART power-on hours. How tiers work
Recent unit reports
Every unit we sell gets a permanent public report. Serial and seal numbers stay on the certificate in the box.
| Unit | Tier | Power-on hours | Tested | Result | Report |
|---|---|---|---|---|---|
| U-492 | Light Use | 12,781 | Nov 1, 2026 | Pass | View report for unit U-492 |
| U-491 | Light Use | 12,781 | Nov 1, 2026 | Pass | View report for unit U-491 |
| U-490 | Light Use | 12,781 | Nov 1, 2026 | Pass | View report for unit U-490 |
| U-489 | Light Use | 12,781 | Nov 1, 2026 | Pass | View report for unit U-489 |
| U-488 | Light Use | 12,781 | Nov 1, 2026 | Pass | View report for unit U-488 |
| U-487 | Light Use | 12,781 | Nov 1, 2026 | Pass | View report for unit U-487 |
| U-486 | Light Use | 12,781 | Nov 1, 2026 | Pass | View report for unit U-486 |
| U-485 | Light Use | 12,781 | Nov 1, 2026 | Pass | View report for unit U-485 |
| U-484 | Light Use | 12,781 | Nov 1, 2026 | Pass | View report for unit U-484 |
| U-483 | Light Use | 12,781 | Nov 1, 2026 | Pass | View report for unit U-483 |
| U-482 | Light Use | 12,781 | Nov 1, 2026 | Pass | View report for unit U-482 |
| U-481 | Light Use | 12,781 | Nov 1, 2026 | Pass | View report for unit U-481 |
Price history
Monthly median of what our own WUH721818AL4200 units sold for.
| Month | Median price |
|---|---|
| Oct 2026 | $489.95 |
WUH721818AL4200 questions
What workloads is this drive suited for?+
As an 18TB 7,200 rpm SAS drive, it fits high capacity, sequential-heavy workloads such as backup targets, bulk archival storage, and nearline storage in servers or storage arrays.
Is this drive compatible with my server or storage system?+
It uses a SAS 12Gb/s interface in a 3.5 inch form factor, so it will work with servers, JBODs, or storage controllers that support SAS 12Gb/s drives in that form factor.
What testing does each drive go through before sale?+
Each unit is run through a sequential and random read/write benchmark, a full extended self-test over the whole surface, a power-on hours cross-check against an independent on-drive log, a NIST 800-88 sanitize with read-back verification, and a SMART health check for reallocated, pending, and uncorrectable sectors.
What does the Light Use tier mean for this drive?+
Light Use covers drives with recorded power-on hours between 500 and 20,000. The units in this listing have between 12,762 and 12,882 hours, with a median of 12,784 hours, all within that range.
How did these drives perform on the benchmark tests?+
Across the 19 tested units, the median sequential read speed was 269 MB/s and the median sequential write speed was 143 MB/s.