Etherium Conduits are a sort of magical redstone repeater, picking up etherium from a linked obelisk and transmitting it another 10 blocks to either the destination or another conduit for extended travel.
Note: The in-game item is called (in the code) "essenceConduit," but the name you will see is "Etherium Conduit."
How to use
To use an etherium conduit, place it down within 10 blocks of an Obelisk, Prism, Aurem, or another etherium conduit. When linking, link your two devices, not the conduits. Conduits automatically create paths to each other, no linking required. (Think of it like a wireless range extender.)
In order to craft an Etherium Conduit, you will need 4 Smooth Stone and a Chimerite, which can be found by mining in the upper-mid levels.