Helios 2 PCIe Thunderbolt Expansion Chassis


Thunderbolt / Thunderbolt 2 / Mac / PC
Use PCIe Expansion Cards with any Thunderbolt Equipped Mac or PC
Helios 2 is the ideal way to access up to two PCIe cards and is perfect for video capturing, video editing, media transcoding, audio processing, ultra-fast networking, data storage, and more via its Thunderbolt interface. Get empowered with the flexibility to upgrade the capabilities of almost any workflow and workstation.
Install Two PCIe Cards + Daisy Chain
Helios 2 supports two half-length (up to 7.75"), full-height, single-width x8 PCIe cards to provide a vast array of expansion options. It also supports the combination of one "single-width" and one "double-width" card for compatibility with cards that utilize a daughter card.
  • Two PCIe card slots + daughter card support
  • Two Thunderbolt 2 ports
  • Thunderbolt daisy-chain six devices plus a display
Thunderbolt Performance Juggernaut
The Helios 2 is the perfect solution to enhance and expand the computing capabilities of any Thunderbolt or Thunderbolt 2 equipped Mac Pro, iMac, Mac mini, Mac laptop, or PC. Utilizing Thunderbolt high-performance technology, Helios 2 is a tour de force that provides the flexibility to use a multitude of PCIe cards with the bandwidth to support their capabilities.
  • Up to 20Gb/s performance
  • Perfect for HD/4K video workflows
  • Perfect for 10Gb/s networking interfaces
  • Perfect for Pro Audio workflows
  • Perfect for Ultra-Fast Datasets + Storage
Durable, Cool, and at the Ready
A whisper quiet variable speed fan keeps the inside of the Helios 2's durable aluminum ventilated chassis running cool. It automatically powers on/off with your computer, so it's at the ready whenever you are.
Lock It Up
Let's face it, you have PCIe cards because they serve an important workflow need. Helios 2 comes with a Thunderbolt cable lock that prevents accidental cable pulls from stopping your work in progress — ensuring your PCIe cards and daisy-chained Thunderbolt devices stay connected.


  • OWC Mercury Helios 2 PCIe Thunderbolt Expansion Chassis
  • High-Quality, Certified, Double-Shielded 1 Meter Thunderbolt cable
  • Helios 2 Thunderbolt cable locking bracket (not compatible with optical Thunderbolt cables)
  • External auto-switching 100/240v 50/60Hz power adapter 12V/7A
  • Helios 2 Manual (View PDF 3.1MB)


Product Specifications:

PCIe cards supported

  • Two half-length (up to 7.75" long), single-width, full-height x8 PCIe 2.0 cards plus one daughter card view compatibility chart

Expansion slot

  • Two x8 PCIe 2.0 (x4 mode)

Device Interface

  • PCIe (PCI Express)

Port Configuration

  • (2) Thunderbolt 2 ports, backwards compatible with Thunderbolt

RoHS Compliant

  • Yes

Max Data Transfer Rate

  • Thunderbolt – 20Gbit/s


  • Bootable on Mac as long as the specific PCIe card installed is bootable

System Requirements

  • Thunderbolt 2 20GBps performance requires a Mac running OS X v10.8.5 or later including OS X Mavericks v10.9.x and an available Thunderbolt 2 port
  • Thunderbolt (original) 10GBps performance requires a Mac running OS X v10.8.5 or later and an available Thunderbolt port
  • PC running Windows 7 SP1, Windows 8.x or later with an available Thunderbolt port (Windows drivers required)1
  • Available Thunderbolt port

External Case Dimensions

  • 6.0 in (W) x 11.0 in (D) x 4.6 in (H)
  • 152.4 mm x 279.0 mm x 117.0 mm

Enclosure Weight (without card)

  • Approximately 3.7 pounds (1.7kg)

Product Manual

PCIe Card Minimum Guaranteed Power

  • 25W

Power Supply

  • UL Listed
  • Universal auto-switching power supply
  • AC input 100/240V 50/60Hz
  • DC output 12V/7A

Operating Environment:


  • 0° C to 35° C (32° F to 95° F)


  • Varies depending on drive mechanism installed







Windows requires a Thunderbolt 2 interface in the computer and in the expansion chassis to support more than two PCIe controllers. Note that some PCIe cards have a bridge to multiple controllers, so it is possible for a single dual-controller PCIe card to reach the limit if not connected via Thunderbolt 2. Not all Mac-compatible PCIe cards are also compatible with Windows. See the PCIe Card Thunderbolt Compatibility Chart for details.