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Synology DX525

The Synology DX525 five-bay expansion unit, front view on a white background

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Synology DX525

Drive bays:
5 x 3.5" SATA HDD or 2.5" SATA SSD, hot-swappable
Expansion port:
1 x expansion port (USB Type-C cable included)
Applied models:
25 series: DS1825+, DS1825neo+, DS1525+, DS1525neo+, DS925+, DS925neo+, DS725+, DS725neo+ (volumes can be created across units; Synology recommends keeping volumes within one chassis for better performance)

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Package details

Model: DX525

Standard US model

Condition:
Confirm new or reconditioned on the listing
Quantity:
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Included essentials:
Main unit, USB Type-C expansion cable, accessory pack, AC power adapter, AC power cord

Important limit: Only works with the 25-series DiskStations listed by Synology; it is not a standalone NAS

How many units?

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Specifications checked November 5, 2026. Full product details

Size and package

Size and placement

Size and weight
166 x 230 x 223 mm, 2.46 kg

In the box

Main unit, USB Type-C expansion cable, accessory pack, AC power adapter, AC power cord

Manufacturer specifications

Synology DX525 5-Bay NAS Expansion Unit

A five-bay expansion unit that adds drive capacity to compatible Synology DiskStations over a single USB Type-C expansion cable, managed by DSM.

Which version should you buy?

Recorded product: Standard US model.

Related models and generations

These are different products. Check their specifications separately.

  • Standard US model

    The base configuration as sold in the US.

Purchase links appear where the exact offer is verified. Confirm the named model, quantity and accessories before ordering.

Why people pick it

  • Adds five hot-swap bays to a compatible DiskStation without downtime (online volume expansion)
  • Can serve as a dedicated local backup target configured as a separate volume
  • 3-year hardware warranty, longer than the 2-year DiskStation base warranty

Know before you buy

  • Only works with the 25-series DiskStations listed by Synology; it is not a standalone NAS
  • Expansion is over one USB Type-C cable, not a direct storage bus
  • Synology recommends keeping volumes inside a single chassis for better performance, which limits cross-unit volume layouts

Full specifications

Drive bays5 x 3.5" SATA HDD or 2.5" SATA SSD, hot-swappable
Expansion port1 x expansion port (USB Type-C cable included)
Applied models25 series: DS1825+, DS1825neo+, DS1525+, DS1525neo+, DS925+, DS925neo+, DS725+, DS725neo+ (volumes can be created across units; Synology recommends keeping volumes within one chassis for better performance)
Drive compatibilitySynology-compatible drives required; consult the compatibility list (HAT5300, HAT3300, SAT5200 Series)
SetupPlug-and-play; bays available immediately on connection, with on-the-fly volume expansion on the host
RAID managementManaged through the host NAS's DiskStation Manager (DSM)
Fans2 x 92 mm fans
Noise level20.4 dB(A)
Power35.37 W access / 7.0 W HDD hibernation; 90 W adapter, 100-240V AC; power recovery synchronized with the host DiskStation
Size and weight166 x 230 x 223 mm, 2.46 kg
CertificationsFCC, CE, BSMI, UKCA, EAC, VCCI, RCM, KC, BIS
Warranty3-year hardware warranty, extendable to 5 years with Extended Warranty Plus
In the boxMain unit, USB Type-C expansion cable, accessory pack, AC power adapter, AC power cord

From manufacturer documentation, checked November 5, 2026. Spotted an error? Tell us.

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