The Redstone Tube is a variation of the Pneumatic Tube. It acts as a tube and Red Alloy Wire in one, capable of transporting items and a redstone signal simultaneously. Redstone Tubes are very handy for reducing wiring clutter, particularly in tight spaces. Use a Jacketed Wire to connect a Redstone Tube to a Red Alloy Wire on a floor, wall, or ceiling.
Note that along with the space saving, there is a slight cost saving as well. Using a Redstone Tube is cheaper than using a separate piece of Red Alloy Wire by 1/4 of an Iron or Copper Ingot per item produced.
Redstone Tubes can be painted with a Paint Brush similar to normal tubes. Two differently colored Redstone Tubes that are adjacent to each other will appear connected and will conduct redstone signals between them, but items will not cross between them. This makes it possible to run Redstone Tubes in parallel maintaining separate item paths but allowing redstone signals to bridge the gap. If redstone signals need to be isolated, then a Cover must be placed between the tubes to prevent them from connecting.