Sonnet Echo Express SE III 3 Slot Thunderbolt 3 PCIE Expansion Chassis

3-Slot Thunderbolt 3 Expansion System for PCIe Cards

Sonnet’s Echo Express SE III is a compact desktop Thunderbolt-to-PCIe card expansion system that enables you to connect three professional PCIe cards—including video capture, audio interface, SAS or SATA HBA, 16Gb or 8Gb Fibre Channel, 10 Gigabit Ethernet, and RAID controllers—at the same time to any Mac with a Thunderbolt 3 port.

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£786.00 £655.00
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The Echo Express SE III 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. 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.

Three PCIe Slots
The Echo Express SE III’s PCIe 3.0 x8 slots support three half-length+, full-height, single-width PCIe cards, or one single-width card plus one double-width card.

Some specialty cards, such as RME’s HDSPe MADI FX card, Blackmagic Design’s DeckLink 4K Extreme, and the Lynx AES16e 50, include a daughter card that mates with and provides additional external connections to the main card.

Thunderbolt 3 - The USB C That Does It All
The Echo Express SE III includes two Thunderbolt 3 (USB-C) ports; the first is used for connection 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 SE III includes 10Gbps USB 3.1 Gen 2 support, meaning you can connect a USB device to the second port using the proper cable or adapter. The Echo Express SE III also provides full support for connecting two 4K displays @ 60Hz or one 5K display @ 60Hz. For connected devices requiring extra power, 15 watts is provided to connected bus-powered devices.

Design Smarts
The inside of the Echo Express SE III is wrapped in a rugged, yet lightweight aluminum outer shell, resulting in a lightweight system small enough to carry in your backpack, yet durable enough to protect the installed PCIe cards securely. The enclosure is ventilated front and back to facilitate airflow over the cards, pushed by a large, quiet, temperature-controlled fan to efficiently cool the system, automatically speeding up and slowing down smoothly as needed—there’s no guesswork in deciding which fan speed to select. Because Sonnet 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.

Nearly Every Thunderbolt 3- and macOS-Compatible PCIe Card Supported
Smaller than the 3-slot Echo Express III-D - Thunderbolt 3 Edition, the Echo Express SE III is still large enough to support nearly every Thunderbolt 3- and macOS compatible card available. With its three x8 slots, the SE III supports PCIe 3.0, PCIe 2.0, and PCIe 1.1 cards up to 7.75 inches long.

Do you have a card in mind but aren’t sure it’s compatible? We’ve worked closely with PCIe card manufacturers to provide a list of compatible cards on our supporting PCIe Card Thunderbolt Compatibility Chart. The chart provides a list of cards that have been tested to be recognized over a Thunderbolt connection and compatible with Thunderbolt technology requirements.

Thunderbolt 3 (40Gbps) Cable and ThunderLok 3 Included
To connect the Echo Express SE III to your computer, Sonnet includes a 0.5-meter Thunderbolt 3 (40Gbps) cable, and a Sonnet ThunderLok 3 Thunderbolt connector retainer clip to secure the cable to the Echo chassis. Accidental cable disconnection can lead to data loss. Sonnet’s ThunderLok 3 is easy to install and use—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.

  • Connects Three PCIe Cards to any Mac with Thunderbolt 3 Ports—Use multiple high-performance PCIe cards at the same time
  • Three PCIe 3.0 Slots—Supports three full-height, half-length+ (up to 7.75 inches long), single-width cards, or one double-width card plus one single-width card
  • 40Gbps Thunderbolt 3 Interface—Offers 2750 MB/s of PCIe bandwidth, doubling the performance of Thunderbolt 2
  • Two Thunderbolt 3 (USB-C) Ports—One port reserved for connection to the computer; second port supports daisy-chaining of up to five additional Thunderbolt devices to your computer, attaching a single USB peripheral device, or connecting up to two 4K displays or one 5K display
  • Rugged Aluminum Housing—Provides robust and secure protection
  • Temperature-Controlled Fan—Automatically operates slower and quieter with cooler cards; provides better cooling for hotter cards
  • Energy Saver Mode—Powers on/off automatically with the computer
  • Nearly Every Thunderbolt 3- and macOS-compatible Card Supported—Works with every Thunderbolt 3- and macOS compatible PCIe card up to 7.75 inches in length
  • Thunderbolt Cable & ThunderLok Included—Includes 0.5-meter Thunderbolt 3 (40Gbps) cable and ThunderLok 3 Thunderbolt connector retainer clip to secure cable from accidental disconnections
More Information


  • Warranty: 1-year
  • Form Factor: Desktop Thunderbolt 3-to-PCIe card expansion system
  • External Connectors:
    • Two Thunderbolt 3 ports
    • 12V power port
  • Expansion Slot:
    • Two x8 mechanical (x8 electrical) PCIe 3.0
    • One x8 mechanical (x4 electrical) PCIe 3.0
  • PCIe Cards Supported:Three half-length (up to 7.75 inches long), single-width, full-height x8 PCIe cards
  • Compatible PCIe Cards: See our supporting PCIe Card Thunderbolt Compatibility Chart for a partial list of compatible PCIe cards
  • Power Adapter: Universal 120W, 100-240V, 50-60 Hz
  • Operating Temperature: 0ËšC to 35ËšC (32ËšF to 95ËšF)
  • Dimensions (WxDxH): 6.5 x 11 x 4.6 in. (16.5 x 27.9 x 11.7 cm)
  • Weight: 2.6 lbs. (1.18 kg)
  • RoHS Compliant: Yes

Note: PCIe cards old separately


Mac Compatibility

  • Mac with Thunderbolt 3 ports
  • Mac with Thunderbolt 2 or Thunderbolt ports and Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter
  • macOS 10.12.1+


Windows Compatibility

  • Not certified for Windows systems at this time.


PCIe Card Compatibility

  • For up-to-date PCIe card compatibility see our PCIe Card Thunderbolt Compatibility Chart
  • Echo Express SE III Thunderbolt 3-to-PCIe Card Expansion System
  • Universal power adapter
  • Power cord
  • 0.5-meter Thunderbolt 3 (40Gbps) cable
  • ThunderLok 3 Thunderbolt Connector Retainer Clip