Conduit

A conduit is a small, waterlogged block.

Usage
Conduit can be used like a beacon, to give all players near it (they must be in a water block) the "Conduit Power" effect. You can create this by adding at least 16 underwater blocks (like prismarine and sea lanterns) around it. It also needs to be underwater. It can also damage hostile mobs in a small radius. Conduit power stops the breath meter from running out, gives underwater vision and increases mining speed.

Trivia

 * When it is activated, the conduit displays the heart of the sea's texture in the center of it's model.