The Ender Watcher is a block added by Quark. While a player is looking directly at it, it will emit a full Redstone signal from all sides. It does not matter the distance the player is from the block, as long as the chunk the Ender Watcher resides in is loaded. The Ender Watcher is disabled if the mod Botania is installed, as the Ender Overseer can be crafted instead.
The recipe below is used instead if Ender Biotite is disabled.