The Variable Speed/Dimming module (shown above) allows for the control of the Aqua Illuminations LED lighting systems as well as adding an additional 4 0-10V variable speed ports.:

Independent control of the white and blue Aqua Illumination LEDs.
Simulate Sunrise/Sunset, Lunar Cycle, Clouds, and Lightning with the Aqua Illumination LEDs.
Adds 4 independent 0-10V variable speed ports to the Apex system.
Plug and Play. Automatically recognized when installed into the system.
Pumps can be dynamically added/removed from the system.
Two AquaBus connectors for flexible expansion via AquaBus.
Comes with 3' AquaBus cable.
Fully upgradeable.
Led Status indicator.
Compatible with Apex and Apex Lite systems.