# USB 3 Micro plug > the latter class of legacy Micro plugs that preceded USB-C **Wikidata**: [Q133873408](https://www.wikidata.org/wiki/Q133873408) **Source**: https://4ort.xyz/entity/usb-3-micro-plug ## Summary The USB 3 Micro plug is a class of legacy Micro‑USB connectors that support SuperSpeed (USB 3.x) data rates and were used before the adoption of USB‑C. It is officially named the **USB 3.1 Micro plug** and includes both “A” (host) and “B” (device) variants. ## Key Facts - **Official name:** USB 3.1 Micro plug (as defined in USB‑31 legacy documents dated 10 May 2025). - **Aliases:** USB 3.0 Micro plug, Micro‑USB 3.1 plug, SuperSpeed USB Micro plug, among others. - **Subclass of:** USB 3 Micro connector, USB 3 plug, and USB Micro plug. - **Variants:** USB 3 Micro‑A plug (host end) and USB 3 Micro‑B plug (peripheral end). - **Different from:** USB 3 Micro receptacle, USB 3 Standard plug, and USB 2 Micro plug. - **Image reference:** Illustration showing both A and B plugs – https://commons.wikimedia.org/wiki/Special:FilePath/USB_connector_illustration,_to_scale,_grouping,_legacy,_USB_3_Micro_plugs.svg. - **Commons category:** “USB 3 Micro plugs”. - **Legacy status:** Part of the “latter class of legacy Micro plugs that preceded USB‑C”. ## FAQs ### Q: What is the difference between a USB 3 Micro‑A plug and a USB 3 Micro‑B plug? A: The USB 3 Micro‑A plug is the host‑side connector, while the USB 3 Micro‑B plug is the device‑side connector; both belong to the same legacy USB 3 Micro plug family. ### Q: How does a USB 3 Micro plug differ from a USB 2 Micro plug? A: A USB 3 Micro plug supports SuperSpeed (USB 3.x) data rates, whereas a USB 2 Micro plug is limited to USB 2.0 speeds. ### Q: Is the USB 3 Micro plug still used in new devices? A: No, it is a legacy connector that was replaced by USB‑C in newer devices, but it may still be found on older hardware. ## Why It Matters The USB 3 Micro plug represents a pivotal step in the evolution of USB connectors, bridging the gap between the widely used USB 2 Micro form factor and the modern USB‑C standard. By adding SuperSpeed capability to the familiar Micro‑USB shape, it allowed manufacturers to upgrade data transfer performance without redesigning device enclosures. This legacy connector is essential for understanding compatibility issues when interfacing older equipment with newer peripherals, and it remains relevant for data recovery, legacy system maintenance, and archival projects. Recognizing the USB 3 Micro plug’s role helps engineers and technicians select appropriate adapters and cables, ensuring reliable connections across generations of hardware. ## Notable For - Being the **latter class of legacy Micro plugs** that existed before USB‑C. - Supporting **SuperSpeed (USB 3.x)** while retaining the Micro‑USB form factor. - Having distinct **A (host) and B (device)** variants within the same family. - Serving as the **official successor to USB 2 Micro plugs** and predecessor to USB‑C. - Being documented in the **USB 3.1 legacy connector specifications** released in 2025. ## Body ### Definition The USB 3 Micro plug is a legacy connector that carries SuperSpeed USB 3.x signals in a Micro‑USB‑sized form. It is officially termed the **USB 3.1 Micro plug**. ### Classification - **Parent classes:** - USB 3 Micro connector (overall connector family) - USB 3 plug (general USB 3 plug category) - USB Micro plug (legacy Micro‑USB family) - **Subclasses / Variants:** - **USB 3 Micro‑A plug** – host side - **USB 3 Micro‑B plug** – peripheral side ### Physical Representation An illustration (see image link above) depicts both the A and B forms, labeled as “USB 3 Micro‑A plug” and “USB 3 Micro‑B plug”. The image is categorized under **USB 3 Micro plugs** on Wikimedia Commons. ### Compatibility & Differentiation - **Different from**: - USB 3 Micro receptacle (the mating socket) - USB 3 Standard plug (full‑size USB 3 connector) - USB 2 Micro plug (lacks SuperSpeed capability) - **Legacy status**: It belongs to the “latter class of legacy Micro plugs that preceded USB‑C”, meaning it was phased out as USB‑C became the universal standard. ### Documentation & Standards The official name and specifications are recorded in three USB‑31 legacy documents dated **10 May 2025**, accessible via the USB‑IF website. These documents define electrical, mechanical, and compliance requirements for the USB 3 Micro plug family. ### Usage Context While no longer produced for new consumer devices, the USB 3 Micro plug remains in use on older smartphones, tablets, digital cameras, and peripheral devices that were released before the widespread adoption of USB‑C. It is often encountered in legacy cable assemblies and adapters. --- *All information presented is derived from the provided source material and associated references.* ## References 1. [Source](https://www.usb.org/document-library/usb-31-legacy-cable-and-connector-revision-10) 2. [Source](https://www.usb.org/document-library/universal-serial-bus-31-legacy-connectors-and-cable-assemblies-compliance-document) 3. [Source](https://www.usb.org/document-library/usb-32-revision-11-june-2022) 4. [Source](https://www.usb.org/document-library/usb-type-cr-connectors-and-cable-assemblies-compliance-document-rev-21b) 5. [Source](https://www.usb.org/document-library/usb-type-cr-cable-and-connector-specification-release-24)