FIELD GUIDESource-led reference
Port & Cable

P137 / Memory cards / Guide

Choose a card reader without guessing from its shape

A reader with the same exterior connector can support a different set of media.

The useful distinction

Identify the card family, consult the exact reader specification, and then document its computer connection. Leave missing facts unknown. The card-reader worksheet provides a scoped documentation result, not a purchase ranking.

Claim inspection dates: 2026-10-03, 2026-10-08 · Independent review pending

Guide note · not an individual product specification

The useful distinction

Understand the requirement.

Treat the card family, exact reader and upstream computer connection as separate checks. [C137A]

SanDisk ImageMate PRO USB-C lists SD, microSD and CompactFlash; those names must not be collapsed into one card family. [C137B]

Sony specifies the MRW-G2 computer interface as SuperSpeed USB 10Gbps (USB 3.2 Gen 2), supplies USB-C–USB-C and USB-C–USB-A cables, and limits its function guarantee to the supplied cable. This interface label is not a measured card-to-computer copy speed. [C137C]

The RDF8 EN_RDF8_PS_1905 sheet says that UHS-II cards work only at UHS-I speeds in that reader. Reading a card therefore does not establish use of its fastest bus mode. [C137D]

Transcend describes RDF8 with a USB 3.1 Gen 1 interface and states that speed varies with host hardware, software, use and storage capacity. No measured read, write or multi-card aggregate rate is adopted here. [C137E]

Bounded facts, visible unknowns

Specifications and limits

Choose a card reader without guessing from its shape facts and limitations
Scoped documentationSony MRW-G2 documentation lists CFexpress Type A and SD, while MRW-G1 lists CFexpress Type B and selected Sony XQD series. [C137A]
Scoped documentationSanDisk ImageMate PRO USB-C lists SD, microSD and CompactFlash; those names must not be collapsed into one card family. [C137B]
Documented distinctionSony specifies the MRW-G2 computer interface as SuperSpeed USB 10Gbps (USB 3.2 Gen 2), supplies USB-C–USB-C and USB-C–USB-A cables, and limits its function guarantee to the supplied cable. This interface label is not a measured card-to-computer copy speed. [C137C]
Documented distinctionThe RDF8 EN_RDF8_PS_1905 sheet says that UHS-II cards work only at UHS-I speeds in that reader. Reading a card therefore does not establish use of its fastest bus mode. [C137D]
Documented distinctionTranscend describes RDF8 with a USB 3.1 Gen 1 interface and states that speed varies with host hardware, software, use and storage capacity. No measured read, write or multi-card aggregate rate is adopted here. [C137E]
Verified device listNot included. Check exact device and accessory documentation.
A boundary, not an omission to guess around.

An exact card, capacity, firmware, operating system and workload may have additional requirements. Use the linked manufacturer documentation for those questions.

Before you connect

What to check

  1. Read the card label and select its exact family.
  2. Use the exact reader model, not a brand-wide assumption.
  3. Check the reader upstream port and computer role separately.
Trace a supported connection class →

Your next step

Move from the form to the requirement.

Compare this field note See the differences without assuming interchangeability.Work through a connection Choose your task before deciding on a cable.Explore this evidence trail Inspect the claims and their dependencies. (private workspace)

The source trail

Evidence for this page

AI-assisted inspection is not independent engineering review. Source scope and access limitations are disclosed below. Procedural checklists are editorial requirements, not hardware measurements.

C137ASource checked · pending review

Sony MRW-G2 documentation lists CFexpress Type A and SD, while MRW-G1 lists CFexpress Type B and selected Sony XQD series.

Sony · MRW-G2 card reader ↗

Locator: Product overview and connection features
Access: public page. Documentation-only family and port scope; no physical test, current stock or price check, measured performance, complete card list, or independent approval.

S105: full source recordSony · MRW-G1 card reader ↗

Locator: Product overview and supported media
Access: public page. Documentation-only family and port scope; no physical test, current stock or price check, measured performance, complete card list, or independent approval.

S106: full source recordInspect review dependencies → (private workspace)

Claim scope: Exact documented product and family scope; no physical test, exact-card certification or end-to-end approval.. Next review due 2027-01-01.

C137BSource checked · pending review

SanDisk ImageMate PRO USB-C lists SD, microSD and CompactFlash; those names must not be collapsed into one card family.

SanDisk · ImageMate PRO USB-C multi-card reader ↗

Locator: Specifications and compatibility; model SDDR-A631-GNGNN
Access: public page. Documentation-only family and port scope; no physical test, current stock or price check, measured performance, complete card list, or independent approval.

S109: full source recordInspect review dependencies → (private workspace)

Claim scope: Exact documented product and family scope; no physical test, exact-card certification or end-to-end approval.. Next review due 2027-01-01.

C137CSource checked · pending review

Sony specifies the MRW-G2 computer interface as SuperSpeed USB 10Gbps (USB 3.2 Gen 2), supplies USB-C–USB-C and USB-C–USB-A cables, and limits its function guarantee to the supplied cable. This interface label is not a measured card-to-computer copy speed.

Sony · MRW-G2 Operating Instructions — 5-019-283-B1 (1) ↗

Locator: PDF page 1, English compatible cards, precautions, specifications and illustrations A–C; printed identifier 5-019-283-B1 (1).
Access: public pdf text. All cards and computers are not guaranteed. Drawing interpreted for this reader only; no manufacturer artwork copied, no card geometry or current OS certification adopted.

S438: full source recordInspect review dependencies → (private workspace)

Claim scope: PDF page 1 English Specifications, connecting instructions and supplied-cable precaution.. Next review due 2027-01-06.

C137DSource checked · pending review

The RDF8 EN_RDF8_PS_1905 sheet says that UHS-II cards work only at UHS-I speeds in that reader. Reading a card therefore does not establish use of its fastest bus mode.

Transcend · RDF8 product sheet — EN_RDF8_PS_1905.pdf ↗

Locator: PDF pages 1–2 visually inspected: page 1 Additional Features, page 2 Operating Environment Note and Compatibility. Page 3 multi-product comparison not adopted.
Access: public pdf text. Page 1 allows two-card insertion while page 2 says it is unsupported. Kept as an unresolved documentation conflict, not a chosen device capability. Filename is not treated as a verified revision date.

S440: full source recordInspect review dependencies → (private workspace)

Claim scope: PDF page 2 Compatibility note; named RDF8 scope, not a rule about all USB readers.. Next review due 2027-01-06.

C137ESource checked · pending review

Transcend describes RDF8 with a USB 3.1 Gen 1 interface and states that speed varies with host hardware, software, use and storage capacity. No measured read, write or multi-card aggregate rate is adopted here.

Transcend · RDF8 product sheet — Transcend-RDF8.pdf ↗

Locator: PDF pages 1–2 visually inspected; card slots, Compatibility, Performance, Ordering Information and three-card insertion wording. No printed revision identifier.
Access: public pdf text. Concurrent-operation wording is compared with S440 and remains unresolved. Document age or hardware revision is not inferred from a filename. No measured aggregate transfer, exact-card or OS certification.

S439: full source recordInspect review dependencies → (private workspace)

Claim scope: PDF page 2 Interface and Performance note; the USB connector subtype is deliberately not assigned in the new device profile.. Next review due 2027-01-06.

Suggest a correction to this field note →

Common questions

Questions this record can help resolve

What do UDMA, UHS and USB mean on a multi-card reader?Keep each card slot’s interface separate from the computer connection.Is VPG the same as a card’s read speed or USB speed?Check sustained-write profile requirements separately from offload claims.

Put this checklist to work.

Choose the exact card family, reader and optional camera slot. Documentation stays separate from physical testing.

Open the card-reader worksheet →

Evidence behind this page

Scope first. Source second. Approval separate.

6 linked sources · 5 scoped claims · 0 sources with inspection/access flags.

Page scope: consumer_reference_expansion

Assessment 2026-10-22 · earliest scheduled source review 2027-01-01. This is a recorded-date assessment, not a live source check. Page-level independent review is not established by this panel.

Inspect 6 source scopes, access limits and dates

S105 · MRW-G2 card reader

Sony · Manufacturer / product-owner domain · inspected 2026-10-03 · due 2027-01-01

Within inspection window

Scoped support: MRW-G2: CFexpress Type A and SD; USB Type-C computer interface, SuperSpeed USB 10 Gbps; supplied Type-C and Standard-A connection cables.

Not established / limitations: Documentation-only family and port scope; no physical test, current stock or price check, measured performance, complete card list, or independent approval.

Locator: Product overview and connection features

S106 · MRW-G1 card reader

Sony · Manufacturer / product-owner domain · inspected 2026-10-03 · due 2027-01-01

Within inspection window

Scoped support: MRW-G1: CFexpress Type B and Sony XQD G- and M-series cards; USB 3.1 Gen 2 Type-C computer interface. Other XQD cards are not established by this scope.

Not established / limitations: Documentation-only family and port scope; no physical test, current stock or price check, measured performance, complete card list, or independent approval.

Locator: Product overview and supported media

S109 · ImageMate PRO USB-C multi-card reader

SanDisk · Manufacturer / product-owner domain · inspected 2026-10-03 · due 2027-01-01

Within inspection window

Scoped support: USB-C interface; SD and microSD UHS-II, UHS-I and non-UHS families, plus CompactFlash up to UDMA 7. CFast and CFexpress are not established by this CompactFlash statement.

Not established / limitations: Documentation-only family and port scope; no physical test, current stock or price check, measured performance, complete card list, or independent approval.

Locator: Specifications and compatibility; model SDDR-A631-GNGNN

S438 · MRW-G2 Operating Instructions — 5-019-283-B1 (1)

Sony · Unclassified publisher domain · inspected 2026-10-08 · due 2027-01-06

Within inspection window

Scoped support: MRW-G2 shared-slot alternatives, Sony card-family wording, USB interface and supplied-cable limitations.

Not established / limitations: All cards and computers are not guaranteed. Drawing interpreted for this reader only; no manufacturer artwork copied, no card geometry or current OS certification adopted.

Locator: PDF page 1, English compatible cards, precautions, specifications and illustrations A–C; printed identifier 5-019-283-B1 (1).

S439 · RDF8 product sheet — Transcend-RDF8.pdf

Transcend · Manufacturer / product-owner domain · inspected 2026-10-08 · due 2027-01-06

Within inspection window

Scoped support: TS-RDF8K2 / TS-RDF8W2 selected media slots, CompactFlash UDMA7, SD/microSD UHS-I, USB 3.1 Gen 1 description.

Not established / limitations: Concurrent-operation wording is compared with S440 and remains unresolved. Document age or hardware revision is not inferred from a filename. No measured aggregate transfer, exact-card or OS certification.

Locator: PDF pages 1–2 visually inspected; card slots, Compatibility, Performance, Ordering Information and three-card insertion wording. No printed revision identifier.

S440 · RDF8 product sheet — EN_RDF8_PS_1905.pdf

Transcend · Manufacturer / product-owner domain · inspected 2026-10-08 · due 2027-01-06

Within inspection window

Scoped support: TS-RDF8K2 / TS-RDF8W2 UHS-II cards at UHS-I speeds and contradictory simultaneous-insertion wording.

Not established / limitations: Page 1 allows two-card insertion while page 2 says it is unsupported. Kept as an unresolved documentation conflict, not a chosen device capability. Filename is not treated as a verified revision date.

Locator: PDF pages 1–2 visually inspected: page 1 Additional Features, page 2 Operating Environment Note and Compatibility. Page 3 multi-product comparison not adopted.

Trace 5 claims to their source records

C137A · P137

Sony MRW-G2 documentation lists CFexpress Type A and SD, while MRW-G1 lists CFexpress Type B and selected Sony XQD series.

Claim scope: Exact documented product and family scope; no physical test, exact-card certification or end-to-end approval.

Source links: S105 · S106 · Evidence trail → (private workspace)

C137B · P137

SanDisk ImageMate PRO USB-C lists SD, microSD and CompactFlash; those names must not be collapsed into one card family.

Claim scope: Exact documented product and family scope; no physical test, exact-card certification or end-to-end approval.

Source links: S109 · Evidence trail → (private workspace)

C137C · P137

Sony specifies the MRW-G2 computer interface as SuperSpeed USB 10Gbps (USB 3.2 Gen 2), supplies USB-C–USB-C and USB-C–USB-A cables, and limits its function guarantee to the supplied cable. This interface label is not a measured card-to-computer copy speed.

Claim scope: PDF page 1 English Specifications, connecting instructions and supplied-cable precaution.

Source links: S438 · Evidence trail → (private workspace)

C137D · P137

The RDF8 EN_RDF8_PS_1905 sheet says that UHS-II cards work only at UHS-I speeds in that reader. Reading a card therefore does not establish use of its fastest bus mode.

Claim scope: PDF page 2 Compatibility note; named RDF8 scope, not a rule about all USB readers.

Source links: S440 · Evidence trail → (private workspace)

C137E · P137

Transcend describes RDF8 with a USB 3.1 Gen 1 interface and states that speed varies with host hardware, software, use and storage capacity. No measured read, write or multi-card aggregate rate is adopted here.

Claim scope: PDF page 2 Interface and Performance note; the USB connector subtype is deliberately not assigned in the new device profile.

Source links: S439 · Evidence trail → (private workspace)

Prepare this page for review → (private workspace)Read the evidence method →

Recorded evidence only. An inspection date, publisher label, source link or generated packet is not independent technical review, hardware testing, fabrication approval or a compatibility verdict.