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The Marshall Stockwell III is a mid-sized portable Bluetooth speaker built around long battery life, a distinctive design and useful wired connectivity. Marshall claims up to 40 hours of playback, and Tom’s Guide reports slightly more than 40 hours in its test at 50% volume. The trade-offs are its 1.3 kg weight, premium price and IP55 protection, which does not make it suitable for submersion.
What the Marshall Stockwell III offers
Marshall’s regional product specifications list Bluetooth 5.3 with SBC, AAC and LC3 codec support, plus USB-C and a 3.5 mm AUX input. The speaker measures 150 × 181 × 72 mm and weighs approximately 1.3 kg. That makes it portable, but heavier than a small grab-and-go speaker.
Marshall describes its sound features as “True Stereophonic” 360-degree sound and “Dynamic Loudness.” Those are the company’s feature descriptions, not independent performance measurements. In their 2026 reviews, TechRadar praised the sound, build and feature set; Tom’s Guide described strong bass, clear mids and bright treble.
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How long does the battery last?
Marshall claims up to 40 hours of playback. Tom’s Guide lists 40 hours as the battery-life specification and says its reviewer achieved just over 40 hours across multiple sessions at 50% volume. That test result belongs to Tom’s Guide; runtime in everyday use will vary with playback conditions and volume.
#1 Best Overall
- 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.
The USB-C connection also has a practical role beyond charging the speaker: Marshall says it can charge a phone. This may help when outlets are scarce, though using the speaker as a power source makes it sensible to keep its own remaining charge in mind.
How rugged is IP55 protection?
IP55 provides dust and water-jet protection, but it is not a submersion rating. Do not treat the Stockwell III as waterproof or use it underwater. TechRadar notes that some competing speakers offer higher water-protection ratings, which matters if you expect a speaker to be submerged or exposed to harsher conditions.
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
What features and connections does it have?
- Bluetooth: Version 5.3, with SBC, AAC and LC3 listed in Marshall’s regional specifications. TechRadar notes that aptX and LDAC are absent.
- Wired audio: A 3.5 mm AUX input is available alongside USB-C.
- App controls: Tom’s Guide describes app-based EQ and presets, firmware updates, Auracast, and customization of the M-button.
- Replaceable components: Marshall says the battery, grilles, silicone sleeve and carry strap are modular replaceable parts. That claim does not by itself establish that individual parts are currently sold in every region.
What reviewers liked—and what they questioned
Strengths noted in reviews
TechRadar’s week-long review, which mainly used Tidal streaming over Bluetooth and USB-C, praised the sound, construction and feature set. Tom’s Guide likewise highlighted the sound and reported a battery test slightly exceeding the advertised 40-hour figure under its 50%-volume test conditions.
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Trade-offs noted in reviews
Both the weight and premium positioning deserve attention. Tom’s Guide considered the speaker somewhat heavy for portable use and the price premium. TechRadar also pointed to the missing aptX and LDAC codecs and to competitors with stronger water ratings. These are reviewer assessments, not a claim that every listener will value those features equally.
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
How it compares with two alternatives
TechRadar’s 2026 review listed the following review-time comparison figures. Prices can change, and the figures should not be treated as current quotes.
| Speaker | Review-time price | Battery figure listed | Dust/water rating |
|---|---|---|---|
| Marshall Stockwell III | $249.99 / £199.99 / AU$379 | 40 hours | IP55 |
| Bang & Olufsen Beosound A1 3rd Gen | $349 / £299 / AU$639 | 24 hours | IP67 |
| JBL Charge 6 | $149 / £129 / AU$229.95 | 24 hours; 28 hours with PlayTime Boost | IP68 |
The figures come from TechRadar’s 2026 review and reflect its review-time table, not a live price check. On those figures, the Stockwell III’s standout distinction is its longer listed battery life; the two alternatives have higher IP ratings. Choose based on whether endurance and Marshall’s feature set matter more to you than greater protection against water ingress or a lower listed price.
Rank #4
- 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
Is the Marshall Stockwell III worth buying?
It is a reasonable shortlist choice if you want a stylish, mid-sized speaker, prioritize long claimed battery life, and value USB-C phone charging, an AUX input and replaceable modules. The strongest caution is the combination of weight and IP55 protection: it is less suited to someone who wants a particularly light speaker or expects submersion-level water resistance. Check your local price and whether its listed codecs meet your needs before buying.
Price and availability vary by region
Marshall Group’s June 10, 2026 Japanese launch announcement gave a Japan price of ¥39,990, with online sales beginning June 10 and authorized-retailer sales beginning June 26. TechRadar’s 2026 review lists $249.99, £199.99 and AU$379 and says the model was released in August 2026. These are region- and publication-specific figures, not a universal current price; check local retailers for availability and today’s price.
Quick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
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.
