Free tools Windows power users keep installed
One-click scans. No signup required.
If you mean a broken-circle USB logo with a number such as 20 or 40, it identifies a USB4 performance tier: USB4 20Gbps or USB4 40Gbps. It does not tell you the port’s charging wattage. A plain circle or other power-shaped icon may mean something else, so check the device’s exact specifications if the marking is unclear.
What a numbered circle beside a USB port means
USB-IF’s 2024 language guideline names USB4 20Gbps and USB4 40Gbps as distinct performance tiers. In this marking, the number indicates the port’s USB4 data-rate tier—not how much power it can deliver. USB-IF’s USB4 language guidelines explain how these performance capabilities are named.
As an Amazon Associate I earn from qualifying purchases.
USB4 uses the USB Type-C connector, but the connector shape alone does not guarantee a particular speed or feature set. USB-IF says USB4 can carry data and display protocols over shared bandwidth; what works depends on the capabilities supported by both connected devices. Its overview describes USB4 operation up to 80Gbps with certified 80Gbps cables, but that does not mean every USB4 port supports 80Gbps. USB-IF’s USB4 overview
Quick wins for a faster PC:
Clear out junk files and repair common Windows errorsFree Scan →Scan for outdated or missing drivers - takes under a minuteDriver Scan →Does the circle symbol tell you how fast the port is?
Only when it is the recognizable numbered USB4 performance mark. The number 20 or 40 corresponds to the named USB4 20Gbps or USB4 40Gbps tier. A numberless circle, semicircle, power glyph, battery mark, or manufacturer-specific icon cannot be identified as USB4 from its shape alone; the title’s description does not establish which marking is on your device.
#1 Best Overall
- Materials and Design: The adapter is made with anti-interference zinc alloy metallic housing and minimalist design with anti-slippery embossments
- Connectors: Engineered for enhanced durability, the male USB C and female USB3 connectors are designed to be plugged and unplugged up to 10000 times
- Compatibility: This USB C to USB 3.0 adapter is compatible with iPhone 17/17e/17 Air/17 Pro/17 Pro Max and MacBook Pro after 2016 and MacBook Air after 2018 and most of the laptops, tablets and smartphones with a USB Type C port
- USB 3.0 Speed in Two: Came in two fast speed adapters in data transfer and charging with premium materials. A foam container is also included for storage and travel
- Compact and Easy to Use: Plug and play, no driver required; Simple structure, lightweight and portability; Also, you can sync or charge your phone with this USB C to USB adapter
USB-IF’s current overview also describes USB4 operation up to 80Gbps over certified 80Gbps cables. Treat that as a capability available in the USB4 family, not as a promise that every USB4 port has an 80Gbps rate. Check the device maker’s specifications for the rate and features of the particular port. USB4 Specification v2.0
Does it indicate charging wattage?
No. A USB4 rate marking identifies data performance, not charging wattage. USB-IF’s cable guidance treats data rate and power capability as separate properties. For example, it shows a USB 20Gbps USB-C-to-USB-C cable rated for 20V at 3A (60W) with a combined 20Gbps/60W logo; that is an example, not a rating that applies to every 20Gbps cable. USB-IF’s cables and connectors guidance
Rank #2
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
To find charging capability, look for a separate power marking and consult the device specifications. Do not infer wattage from a circle, the USB-C connector, or a 20/40 data-rate number.
How to check an unclear marking or choose the right cable
- Identify the exact marking. If it is a numbered USB4 logo with 20 or 40, read it as the corresponding USB4 performance tier. If it is unnumbered or looks like a power or battery icon, do not assume it is a USB4 mark.
- Check the device documentation. Search the manual or specification page for the exact make and model. Confirm the port’s stated data rate, display support, and power capability; a connector alone does not guarantee those features.
- Check both ends of the connection. USB4 connections operate at the best capability mutually supported by the host and peripheral. A cable cannot add a capability that either device lacks.
- Match the cable to your needs. For high-speed data or display use, choose a USB-C cable whose stated data-rate rating meets the devices’ supported rate. Check its power rating separately if charging matters. USB-IF provides cable marking guidance, including the example above.
USB-IF says its certified USB logos are for products that have passed compliance testing and are currently on its Integrators List. That condition applies to certified USB-IF logos; it should not be generalized to every informal marking manufacturers put beside ports. USB-IF’s logo license information and USB logo usage guidelines
Quick Recap
Best Value
- Anker Advantage: Join the 55 million+ powered by our leading technology.
- Widely Compatible: Transform any USB-C port into a USB-A port and connect up a wide range of USB-A devices including external hard drives, phones, mice, printers, and more.
- Strong and Stylish: Finished in Space Gray and constructed from premium scratch-resistant aluminum, the adaptor not only blends seamlessly with your MacBook Pro but also withstands the wear and tear of day-to-day use.
- Superior Connectors: Engineered for enhanced durability, the male USB-C and female USB-A 3.0 connectors are designed to be plugged and unplugged up to 10,000 times—basically for life.
- Space for Two: The ultra-slim form factor ensures there’s space to plug two adaptors side by side into your MacBook Pro’s USB-C ports.
Rank #4
- PACK OF 2 & GREAT VALUE：Package includes 2pcs dual port wall charger enabling you keep one at home, one at work and one for traveling. Great valued alternatives to the brand. Various vibrant colors available to easier to identify which one is for your gadgets
- WIDE COMPATIBILITY：Usb c charging block is widely compatible with iPhone 14/14 Plus/14 Pro/14 Pro Max/iPhone 13/13 Pro Max/iPhone 12/12 Mini/12 Pro/12 Pro Max/iPhone11/11 pro/11pro max /XS/XS Max/XR/X/8/7/6, iPad Pro 11"2020/iPad Air 3 10.5" and more latest smartphones and tablets
- EFFICIENT CHARGING：Charging wall adapter that delivers a sturdy full power for efficient charging, Allowing you to quickly charge your devices especially when people in a hurry
- SMART SAFE GURAD IN CHARGING：Usb-c wall charger also includes an intelligent chip that safeguards your phone against overheating, overvoltage, and general electrical surges. You will not regret getting this charging block for the best charging performance
- DUAL PORT YET COMPACT：Type c charging block with dual port in a single plug gives you the flexibility to use an older USB-A cable as well as the USB-C cable. It is also made into a compact cube that doesn’t take much spaces. Perfect for tight places or carry on the go
Rank #3
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
