The control manifold that runs Howe's hydraulic jack system. Howe says the manifold is electrically operated, so a switch and buttons in the truck let the driver raise and lower the jacks while the co-driver changes the tire.
You'll need it to run the 36 inch (960-1002) or 48 inch (980-1002) jack. Howe also posts wiring and plumbing schematics and manifold instructions on its site.
Howe Performance part number 960-1001.