NOTE: This will only appear in-game if you also have Baubles by Azanor installed.
The Magnetization Controller is a belt that you can wear that gives you the ability to toggle the Magnetization effect. Once equipped in the Baubles UI belt slot, you can press the toggle key (default is the 'y' key) to toggle the ability. This item is useful for when your inventory is full and you have items floating all around you. You simply press the toggle key and they drop to the ground like normal.
The controller comes pre-enchanted with Magnetization 3 so you don't need any other Magnetized tools or armor to still have the Magnetization effect.