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Small black USB 3.0 microSD card reader, compact rectangular shape

SanDisk

SanDisk SDDR-B531-GN6NN Micro SD USB 3.0 card reader 170 MB/s

SKU CH-PG7P-PJBQ1 MPN SDDR-B531-GN6NN

Compact microSD reader with USB 3.0 interface delivering up to 170 MB/s transfer speeds

  • TypeMicro SD
  • Slots1
  • Installation TypeExternal
  • ColorBlack
  • InterfaceUSB 3.0
  • CompatibilitymicroSD
  • Fast UHS-I transfers up to 170 MB/s
  • USB 3.0 moves files up to 10x faster than USB 2.0 readers
  • Compact design at .35 x .82 x 1.20 inches
  • Durable build for frequent file transfers
  • Backwards compatible with USB 2.0 ports

Compact Micro SD Reader

The SanDisk MobileMate SDDR-B531-GN6NN is a tiny external card reader built for microSD cards. It connects through a USB 3.0 port and supports UHS-I transfer speeds of up to 170 MB/s. The black casing measures 0.35" x 0.82" x 1.20", making it easy to carry in a pocket or laptop bag. It suits photographers, drone pilots and mobile users who need quick access to card data on any computer.

Upgrade From USB 2.0 Readers

This reader replaces older USB 2.0 card readers that cap transfer rates at much lower speeds. With USB 3.0, it moves files up to 10x faster than those legacy devices, cutting wait times when offloading large batches of photos or video clips. The jump is worth it whenever you regularly shift multi-gigabyte folders and want the process finished in seconds rather than minutes. Backward compatibility with USB 2.0 ports ensures it still works on older machines, though at reduced speed.

Sustained Transfer Behaviour

Under continuous load, the reader maintains the UHS-I link speed allowed by the inserted microSD card and the host USB 3.0 controller. Thermal throttling is minimal because the compact design has no active cooling and draws little power. Performance stays consistent across long copy sessions as long as the source card can sustain its rated write or read rate. The single-slot layout means only one card operates at a time, avoiding bus contention.

Highlights

  • Fast UHS-I transfers up to 170 MB/s
  • USB 3.0 moves files up to 10x faster than USB 2.0 readers
  • Compact design at .35 x .82 x 1.20 inches
  • Durable build for frequent file transfers
  • Backwards compatible with USB 2.0 ports

Specifications

BrandSanDisk
SeriesMobileMate
ModelSDDR-B531-GN6NN
TypeMicro SD
Slots1
Installation TypeExternal
ColorBlack
InterfaceUSB 3.0
CompatibilitymicroSD
Dimensions0.35" x 0.82" x 1.20"
FeaturesTransfer Speeds of up to 170MB/s
Move big files fast, move a lot of files fast or just make frequent file transfers that much quicker.
Move Files up to 10X Faster than with USB 2.0 Readers 2
The MobileMate USB 3.0 microSD card reader delivers the performance of USB 3.0—so you can move files faster and get back to all the other things you would rather be doing.
Compact and Durable Design
With its small but sturdy design, the MobileMate® USB 3.0 microSD card reader is easy to take anywhere and can hold its own when tossed in your bag with all your other gear.
USB 3.0-Compatible
The Mob
Shipping weight0.02 kg
Package size152 × 101 × 9 mm

Questions about this item

How much space does the 0.35" x 0.82" x 1.20" reader need beside a USB port?

The reader measures 0.35" x 0.82" x 1.20", so it fits beside most ports without blocking adjacent slots.

What step do people miss when plugging the USB 3.0 reader into a computer?

Insert the microSD card fully until it clicks, then plug the reader into a USB 3.0 port for 170 MB/s speeds; USB 2.0 ports fall back to slower rates.

When should the SDDR-B531-GN6NN be replaced?

Replace the reader if the USB connector becomes loose, the card slot no longer clicks, or transfer speeds drop well below 170 MB/s on a known-good card.

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