The Auto-Enchanter is added by the MineFactory Reloaded mod, and is uses liquid mob essence provided by a Grinder to enchant items randomly at a customizable level. Like all MFR Machines, it runs on either BuildCraft or Industrial Craft 2 power. In choosing enchantments, it uses the same algorithm as the standard enchanting table.
(Note : For some reasons, it crashes the world if you use BuildCraft Pipes. Pneumatic tubes are recommended.)
When you right-click on the auto-enchanter, a gui will appear like the one to the right. This is where you can customize your target enchantment level. The amount of energy required to enchant an item depends on its target enchantment level, therefore level 4 will be cheap, while level 30 will be much more expensive. The Auto-Enchanter can be used to take a second (and more) pass at enchanting items, but note that the cost goes up extremely fast relative to the number of enchantments already on the item.