The Writer is a block in Refined Storage.
When opened, all the reader / writer channels on the Refined Storage network are visible. The player can create or remove channels to their liking.
The Writer is a block that exposes the items, fluids, energy and / or redstone signal from the bound channel. The data that is received is sent from the Reader.
Note that the Writer doesn't auto-push any of the supported types. You have to extract it manually.