Echo Express SEL


Echo Express SEL (Thunderbolt 3 Edition)

1-slot Desktop Thunderbolt 3 Expansion System for Low-profile PCIe Cards

Connect a Low-profile PCIe Card to Computers with Thunderbolt 3 Ports


Echo Express SEL (Thunderbolt 3 Edition)

1-slot Desktop Thunderbolt 3 Expansion System for Low-profile PCIe Cards

Connect a Low-profile PCIe Card to Computers with Thunderbolt 3 Ports

Shopping for a new computer? The latest ultra-light notebooks, small form factor and all-in-one Mac®, Windows®(1), and Linux® computers with Thunderbolt™ 3 ports are slender marvels of engineering that come with a cost—there’s nowhere to install PCIe cards that provide additional connectivity and processing capabilities. Sonnet’s Echo™ Express SEL (Thunderbolt 3 Edition) is a compact, desktop Thunderbolt™ 3 to PCIe card expansion system that enables you to connect a low-profile PCIe card to any computer with Thunderbolt 3 ports.

The Thunderbolt 3 Connection

Through its x8 PCIe 3.0 slot, this little expansion system supports many low-profile PCIe cards (Thunderbolt-compatible 16Gb and 8Gb Fibre Channel, 40Gb and 10Gb Ethernet, video capture and processing, SAS and SATA host bus adapters, and RAID controllers) and connects it to your computer through a single Thunderbolt 3 cable.

Key Features
PCIe Card Icon Connects a PCIe Card

Use high-performance PCIe cards with any computer with a Thunderbolt 3 port.


Number 1 Icon One PCIe 3.0 x8 Slot

Supports one low-profile PCIe card.


40Gbps Icon 40Gbps Thunderbolt 3 Interface

Offers 2750 MB/s of PCIe bandwidth, doubling the performance of Thunderbolt 2.


Performance Icon Small Package. Full Performance.

Smallest Thunderbolt 3 to PCIe card expansion system available; supports the most popular low-profile, Thunderbolt-compatible PCIe cards at full performance.

Thunderbolt 3 Ports Icon Two Thunderbolt 3 Ports

One port connects to computer; second port supports daisy-chaining of up to five additional Thunderbolt peripheral devices.


Sound Icon Remarkably Quiet

Temperature-controlled, variable-speed fan automatically and quietly cools the card.


Energy Saver Icon Energy Saver Mode

Powers on/off automatically with the computer.


Rugged Icon Rugged Aluminum Housing

Provides robust and secure protection.


Power Icon Power for Peripherals

Daisy chain port provides up to 15W of power to connected peripherals.


Nearly Every Thunderbolt-compatible, Low-profile PCIe Card Supported

The Echo Express SEL accommodates a wide variety of PCIe cards. Do you have a card in mind but aren’t sure it’s compatible? We’ve put together a list in our supporting PCIe Card Thunderbolt Compatibility Chart (PDF). There you’ll find cards identified as conforming to Thunderbolt technology requirements, and organized by fit and power compatibility with specific expansion system.

Smart Design, Inside and Out

Aluminum Enclosure. Auto Power On/Off.
With a shell crafted of rugged and lightweight aluminum, Echo Express SEL securely houses the installed PCIe card. Inside, the card is protected through the use of a variable-speed, temperature-controlled fan which ensures the card and chassis’ components remain reliably cool. The fan automatically speeds up as necessary to cool the card when it’s hot, and slows down when it’s cool. Since Echo Express products automatically power on and off with your computer, there is no power switch on the chassis, ensuring you don’t waste energy by forgetting to turn it off.
Designed for Low-profile PCIe Cards

Echo Express SEL supports one half-length (up to 6.6 inches long), low-profile, single-width PCIe card; PCIe 1.1, PCIe 2.0, and PCIe 3.0 cards are supported. Many of the most popular Thunderbolt-compatible high-speed networking and storage controller cards are a perfect fit, and even the BlueFish 444 Epoch 4K Neutron video card can be accommodated.


Quiet Please
Echo Express SEL is designed to be ultra-quiet so that it can be comfortably used in noise-sensitive environments. The airflow path within the chassis has been specially designed to enable the fan to quietly and efficiently cool the installed card at all times, even during peak operation.

Included at No Extra Charge

Thunderbolt 3 Cable. ThunderLok 3.

Sonnet includes a 0.7-meter Thunderbolt 3 (40Gbps) cable that supports Thunderbolt 3’s full 2750 MB/s PCIe bandwidth. Sonnet also provides a ThunderLok 3 Thunderbolt connector retainer clip that prevents accidental cable disconnections—just slide it over one end of the cable, and then plug in the connector and secure it to the chassis by turning a thumbscrew. Because of its unique design, ThunderLok remains on the cable so it won’t get lost when not in use.

Fastest External Interface Available

Echo Express SEL (Thunderbolt 3 Edition) features a 40Gbps Thunderbolt 3 interface, which offers double the PCIe bandwidth and connectivity of Thunderbolt 2, and yields up to 2750 MB/s of bandwidth, enabling it to support 4K video capture and processing cards at high frame rates, and 16Gb FC cards and dual-port 10GbE cards at full performance.


Thunderbolt 3 –
The USB-C That Does It All

Echo Express SEL (Thunderbolt 3 Edition) includes two Thunderbolt 3 ports; the first connects it to your computer, while the second supports daisy chaining of up to five additional Thunderbolt peripheral devices to a single port on your computer. The SEL also includes 10Gbps USB 3.2 Gen 2 support, meaning you can connect a USB device to the second port using the proper cable or adapter. For your connected peripherals requiring extra power, 15 watts is provided to connected bus-powered devices. With the ability to handle multiple demanding, high performance PCIe cards, support for connecting two 4K displays @ 60Hz or one 5K display @ 60Hz, and support for a vast array of Thunderbolt and USB devices, Thunderbolt 3 is a leap forward in every way.


Up to Twice the Performance of Thunderbolt 2







Connect computer to one port on the Echo Express SEL (Thunderbolt 3 Edition) and daisy chain up to 5 additional Thunderbolt devices (plus two 4K monitors, one 5K display, or one USB 3.0 device)

Additional information

Weight 840 g
Dimensions 10.3 × 21.0 × 7.3 cm
Form Factor


External Connectors

2x Thunderbolt 3 ports
1x 12V power port

Expansion Slot

One x8 PCIe 3.0 slot
x8 mechanical; x4 electrical (Thunderbolt 3 spec)

PCIe Cards Supported

1x low-profile PCIe card

In The Box

Echo Express SEL (Thunderbolt 3 Edition)
Universal power adapter
Power cord
0.7-meter Thunderbolt 3 (40Gbps) cable
ThunderLok 3 Thunderbolt Connector Retainer Clip


Mac Compatibility

Mac (Intel®) with Thunderbolt 3 ports
Mac (M1) with PCIe cards that have M1 compatible drivers
Mac with a Thunderbolt 2 or Thunderbolt port with an Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter plus a Thunderbolt 2 cable (both sold separately)
macOS® 10.12.6+
macOS Big Sur compatible

Windows Compatibility(1)

PC with Thunderbolt 3 ports
Windows 10 (64-bit Edition Version 1809 or greater)
Important Note: Windows computers require the latest BIOS and Thunderbolt drivers to support this product. Check with your computer manufacturer for update information.

Linux Compatibility

Linux® computer with Thunderbolt 3 ports
Linux Kernel 5.0+


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