Pneumatic Tubes are the main item transfer method in RedPower 2. They have automatic internal routing and send items to the closest valid destination. Valid destinations are any block with an inventory, such as Chests, Deployers, and Furnaces / Electric Furnaces. If an inventory fills up and cannot accept any more items, it will cease to be a valid destination and items will be sent to the next valid destination. If no valid destinations exist, the tube will bounce back the items into the sender, and will no longer send. Note that unless a player uses a Golden Transport Pipe, these are much faster than any BuildCraft pipes.
Items without a valid destination will bounce around in the Pneumatic Tubes until one becomes available. Items are most commonly supplied to the tubes using Filters, Transposers, Sorting Machines, and Block Breakers. An Automatic Crafting Table Mk II must be used with these.