Vis Relay (Thaumcraft 4)

The Vis Relay is a transparent block added by Thaumcraft 4. It is used to extend centivis (CV) paths from another relay or an Energized Node to another relay or CV-using device. Its maximum range is 8 blocks. Relays can be attuned to a certain color to prevent the relay from transferring over to an undesired one. Attune them by right-clicking on the relay with an aspect shard of the desired color, or cycling through all possible colors by right-clicking with a wand in hand.

Relays can only accept CV from one source, though it can output to multiple Relays.