This is the TetherBoost Pro Core Controller, a device designed specifically to boost and stabilize a USB 3.0 connection. While laptops are built to be as efficient as possible, they often sacrifice power for USB stability that is crucial to photographers. With this TetherBoost Pro Core Controller you can transfer images straight from your camera to your laptop with stable, full USB 3.0 speed. Linked with separately sold Active Extension cables, it can maintain a stable USB connection (indicated by its LED) for up to 14.6m – 19.8m with a second TetherBoost Pro. An additional power source isn’t required but this TetherBoost Pro Core Controller can be powered by an external battery pack or wall socket to save laptop and camera battery life. If you desire a stable USB 3.0 connection between your camera or digital back and computer, then this TetherBoost Pro Core Controller is your solution. Order yours today.