"Legacy" on this site means an older support generation, not broken -- but a used camera still deserves its own checklist before you buy.
Older or used cameras are often the best value in this dataset -- especially ones labeled "Great Value" on the Synology database, or anything in the "Legacy" section that's still available at a meaningfully lower price than current-generation equivalents. Before buying one, particularly secondhand on eBay, it's worth checking a few things that don't come up when buying new.
On this site, "legacy" specifically means a camera requires an older Synology Device Pack version (or, for QNAP, an older QVR Pro firmware baseline) than the "current" threshold -- see how Device Pack versions work for the full explanation. It is fully compatible with any up-to-date Surveillance Station or QVR Pro install running that Device Pack version. It is not a statement that the camera is discontinued, defective, or unsupported by its manufacturer -- treat it as "older support generation," not "broken."
Camera product lines frequently ship multiple hardware revisions or regional variants under the same base model name, with different suffixes for PoE vs. Wi-Fi versions, resolution tiers, or firmware generations. Compare the exact model number on the listing (and, ideally, visible in listing photos of the camera's label or box) against the exact model page on this site before buying -- a close-but-not-exact model match can mean a different resolution, a missing feature, or a different Device Pack/QVR Pro requirement than you expect.
PoE cameras don't need a separate power adapter if you already have PoE infrastructure, but a used listing sold as "camera only" won't include a PoE injector if you don't -- see PoE vs. Wi-Fi cameras if you're not sure whether you need one. Check whether mounting hardware, the original power supply (for non-PoE units), and any proprietary cables are included, since replacing manufacturer-specific mounting hardware can be surprisingly hard to source separately for an older model.
Outdoor camera housings rely on weatherproofing seals that degrade with age and sun exposure -- ask whether the camera was used outdoors and for how long. IR illuminators and mechanical day/night IR-cut filters are also wear points worth asking about specifically, since a camera can look cosmetically fine while having a failed night-vision mode. A seller with genuine testing history (ideally photos or a short video of the camera actually running) is a better sign than a generic "untested" or "pulled from a working system" description.
eBay listings shown on this site are pre-filtered to exclude items marked for-parts, not-working, or sold as multi-unit lots -- see Methodology for the exact rules. That filtering catches the most obvious red flags, but it isn't a substitute for reading the actual listing, checking seller feedback, and confirming eBay's own buyer protection and return policy apply before you commit -- this site verifies that a listing exists and matches the model, not the physical condition of any individual unit.