The Crusher is an ore doubling device from Metallurgy 4. It is powered with fuel, just like the vanilla furnace. It's inside the category of Machines.
When given ores, it gives 2 dust for each ore. When given ingots, it returns 1 dust per ingot.
Most of the blank spaces in the GUI are unused. There is only one active fuel slot and one active input slot. However, there are three output slots, which can accept more than 64 dust.
CraftingThe Crusher is crafted in a crafting table with 3 copper ingots on the top, a machine frame in the middle, a furnace on the bottom and 4 iron ingots to the sides.
4.0.0 - The many tiers have been removed, leaving a single crusher.
4.0.6 - Rhino Kneel's texture was replaced with the texture from the new artist, EratoNysiad
Notice the unused spaces.