The Node Router is used to link Nodes together into a Network. Its functionality is straightforward - Simply hold [Shift] and [ПКМ] while aiming at a node, then do the same to another node within 16 blocks. These two nodes are now linked. If you want to de-select a node, [ПКМ] on any other block. See the entry on Routing Nodes for more information.
A slightly magical stick.