This article covers CORSAIR EX300U 1TB USB-C 外付けSSD (ソリッドステートドライブ).

Overview

CORSAIR's EX300U is a 1TB portable SSD that connects via USB 3.2 Gen 2 Type-C, delivering read and write speeds up to 1,100MB/s. It's designed for users who need fast, on-the-go storage without the hassle of cables or bulky drives. The standout feature is the built-in MagSafe magnetic ring on the back, allowing the drive to attach securely to iPhone 12 and later models, as well as any metal surface, making it incredibly convenient for mobile content creators and everyday users.
Weighing just 40 grams and roughly the size of a credit card, the EX300U slips easily into a pocket. The package includes two USB-C cables: a straight 0.3m cable and a right-angle 7cm cable, both suitable for connecting to phones, tablets, or laptops. It works plug-and-play with Windows, macOS, iOS, iPadOS, and Android, with no driver installation required.
Positioned as a mid-range portable SSD, the EX300U competes directly with Samsung T7 Shield and SanDisk Extreme Portable, but adds the unique MagSafe attachment that no other mainstream external SSD offers. It's a niche product that excels for iPhone users seeking seamless external storage.

Compatibility Guide

The EX300U uses a USB Type-C connector with USB 3.2 Gen 2 (10Gbps) interface. It works with any device that has a USB-C port and supports mass storage. For PCs with only USB-A ports, a USB-C to USB-A adapter is required (not included).
Supported platforms: Windows 10/11, macOS 10.15+, iOS/iPadOS 13+, Android 10+. It is not officially tested on game consoles, but it may work as external storage on PlayStation 5 or Xbox Series X|S if formatted to exFAT.
The MagSafe ring is compatible with iPhone 12 through iPhone 16 series, and any MagSafe-compatible case on Android phones. The magnetic hold is strong enough for casual use, but not as tenacious as Apple's official MagSafe accessories. It can also stick to bare metal surfaces on laptops or desks.

Product Info

The CORSAIR EX300U launched in late 2025 with a retail price around ¥32,800 in Japan. It comes with a 3-year warranty from CORSAIR. The drive is formatted exFAT out of the box, so it works across Windows and macOS immediately.
In the market, it's a mid-tier portable SSD. The 1,100MB/s sequential speed is typical for USB 3.2 Gen 2 drives. The MagSafe feature is the main differentiator, making it ideal for iPhone users who frequently shoot high-bitrate video.
Key specs: 1TB capacity, USB 3.2 Gen 2, 1,100MB/s read and write, 40g weight, gray color, bundled cables (0.3m straight, 7cm right-angle).

Best Use Cases

iPhone Video Creators (ProRes)
For users shooting 4K ProRes on iPhone 15 Pro/16 Pro, the EX300U can be attached magnetically to the back of the phone and used as a direct recording destination. This frees up internal storage and allows long recording sessions. The 1,100MB/s write speed is sufficient for 4K/60fps ProRes.
Mobile Professionals
Business travelers who need to carry presentations, documents, and media between a laptop and a phone will appreciate the compact size and cross-platform compatibility. No drivers, no Wi-Fi setup — just plug in and access files.
Gamers with Full Internal Storage
As a backup drive for game captures, screenshots, or moving old game installs to free up internal SSD space, the EX300U works well. However, running modern games directly from it will result in longer load times compared to internal NVMe SSDs, so it's not suitable for a primary game library.
Android Users with Metal Surfaces
The magnetic ring can attach to any ferromagnetic surface, such as a metal phone case or a laptop lid. This provides a convenient way to keep the drive nearby, though the hold may not be as secure as on an iPhone.

Things to Consider

The EX300U's speed ceiling is 1,100MB/s, which is the practical limit of USB 3.2 Gen 2. If you frequently transfer large video files and need the fastest possible throughput, consider a Thunderbolt 4 or USB4 external SSD (e.g., Samsung T9 or SanDisk Pro-G40), which can reach 2,000–3,000MB/s. The EX300U is not a speed king, but it's more than adequate for daily backups and media files.
The MagSafe magnetic strength is moderate. It holds the drive securely on a stationary phone, but if you're running or moving vigorously, the drive could detach. Consider using a short cable to tether it to the phone for extra security.
Only one USB-C port is available on the drive. Pass-through charging is not supported — when connected to a phone, you'll need to charge the phone separately. Also, the drive draws power from the host device, so using it with a phone may drain the battery faster.
Competitors like the Samsung T7 Shield (IP65 rated, 1,050MB/s) and SanDisk Extreme Portable (1,050MB/s) offer similar speeds and often sell for less. The EX300U's premium is justified only if you need the MagSafe integration. If you don't own an iPhone, the value proposition weakens.

FAQ

Q: Can I record ProRes

Product Disclosure (Amazon)

  • Manufacturer: CORSAIR
  • Seller: ジュリア本店
  • Fulfilled by: ジュリア本店
  • ASIN: B0FS29J672
  • Note: This article covers a manufacturer-made product based on Amazon listing details.