HP · ProLiant OEM
781518-B21 is HP ProLiant OEM 1.2TB SAS-12G. 2 of its 2 segments are defined in HP's published documentation and decoded below; the rest are not publicly documented and are marked as such. 2 live listings below.
| Segment | What it means | Source |
|---|---|---|
| 781518 | HPE part identifier. HPE publishes which product each number corresponds to, but does not publish a character-level grammar for this field. | HPE |
| B21 | Option part number - the orderable product as sold, typically including mounting hardware. | HPE |
We decode only what the manufacturer documents. There is a large body of community knowledge about the undocumented segments above, much of it probably right, and none of it published by HP - so it does not appear in this table. A reading nobody can check does not belong in a column headed “what it means”. Grammar reference: HPE - spare part numbers and how to find them.
781518-B21 is HP ProLiant OEM, a 1.2TB hard drive on SAS-12G. Being a SAS device, it needs a SAS host bus adapter or backplane - it will not run from a motherboard SATA port, though a SATA drive will run on a SAS controller.
We currently track 2 live listings against this exact part number, across both new and refurbished stock, which frequently carry different warranty positions even when the part number is identical. 10 sibling part numbers are documented below - these are the numbers most often mistaken for this one, and the table marks which fields actually differ.
| Manufacturer | HP |
| Family | ProLiant OEM |
| Capacity | 1.2TB |
| Interface | SAS-12G |
| Product class | HDD |
These are the part numbers most often confused with 781518-B21. The differences below come from the same vendor documentation as the decode above - where a field is not documented, the row leaves it blank rather than guessing.
| Part number | Capacity | Interface | Format | |
|---|---|---|---|---|
| 508011-001 | 1TB | SAS-6G | in catalogue | |
| 653959-001 | 3TB | SAS-6G | in catalogue | |
| 695510-B21 | 4TB | SAS-6G | in catalogue | |
| 695842-001 | 4TB | SAS-6G | in catalogue | |
| 781578-001 | 1.2TB | SAS-12G | in catalogue | |
| 791034-B21 | 1.8TB | SAS-12G | in catalogue | |
| 834031-B21 | 8TB | SAS-12G | in catalogue | |
| 846523-004 | 4TB | SAS-12G | in catalogue | |
| 861754-B21 | 6TB | SAS-12G | in catalogue | |
| 872745-001 | 4TB | SAS-12G | in catalogue |
Amber cells differ from 781518-B21; grey cells match it.
| Listing | Condition | Pack | $/TB | Price | |
|---|---|---|---|---|---|
| HP 781518-B21 1.2TB 12G SAS 10K | Refurb | single | $45.83 | $55.00 | Buy |
| HP 781518-B21 1.2TB 12G SAS 10K | New | single | $62.50 | $75.00 | Buy |
A manufacturer part number does not imply a manufacturer warranty, and this is where part-number buyers lose the most money. OEM stock, integrator pulls and gray-market units all reach the market under the maker's own numbering. Retailers selling them sometimes state plainly that the manufacturer warranty is none; others simply do not mention it, which is not the same as it being covered.
Coverage attaches to the individual unit and its serial number, not to the part number. That means the only reliable answer comes from the manufacturer, about the specific drive you are being sold.
Ask the seller for the serial number and check it with HP directly before buying. We do not link a checker for this manufacturer because we have not verified one.
A seller warranty is a different promise from a different company. What each warranty tier actually covers · Verify on arrival
4 in-stock listings · same capacity, any part number · ranked by live cost per tb, refreshed every few hours
| Drive | Capacity | Interface | Recording | Condition | $/TB | Price | |
|---|---|---|---|---|---|---|---|
| HP 781578-001 1.2TB 12G SAS 10K 781578-001 | 1.2TB | SAS-12G | CMR | NEW | $33.33 | $40 | Buy |
| HGST 1.2TB 10K SAS 12G 2.5 HUC101212CSS600 | 1.2TB | SAS-12G | CMR | NEW | $44.17 | $53 | Buy |
| HP 781518-B21 1.2TB 12G SAS 10K 781518-B21 | 1.2TB | SAS-12G | CMR | REFURB | $45.83 | $55 | Buy |
| HP 781578-001 1.2TB 12G SAS 10K SFF 781578-001 | 1.2TB | SAS-12G | CMR | REFURB | $46.67 | $56 | Buy |
Every 1.2TB drive we track, ranked by cost per terabyte.
781518-B21 is HP ProLiant OEM 1.2TB SAS-12G. 2 of its 2 segments are defined in HP's own published documentation - the decode table on this page shows each one with the document that defines it. The remaining segments are not publicly documented, and we say so rather than repeating a community guess as fact.
Not necessarily, and the part number cannot tell you. Coverage depends on how the individual unit entered the market and whether it was registered, not on its model designation. OEM and gray-market stock reaches the market under manufacturer part numbers regularly and frequently carries no manufacturer warranty at all - some retailers print exactly that on the listing. Check the specific serial with the manufacturer before buying.
Both are in the ProLiant OEM range. The clearest difference is capacity - 1.2TB against 1TB. They differ in interface: SAS-12G against SAS-6G, which decides whether the drive fits your controller. The variant table on this page lists every sibling we document with what differs.
We track 2 live listings carrying this part number, shown above with condition and cost per terabyte. Prices come from Amazon US and are re-checked continuously; the buy links go to the live listing because the price can change between our check and your click.
Because more than one organisation names it. The manufacturer assigns a model number describing the product; a server vendor buying it in volume assigns its own spare-part number for its service catalogue; distributors sometimes add another. All identify the same physical drive, which is why one number returns listings that look like a different product. Our part number index explains the pattern per vendor.