BuildCraft was the original mod to introduce Minecraft Joules (MJ) but has since adopted the widely used Redstone Flux (RF) power system which many other mods use. Machines such as the Quarry, Pump, and Builder can be powered using one of the three engines BuildCraft adds. Any RF power generating system can be used, though. BuildCraft also introduces two new liquids, Oil and Fuel, to provide increased energy output. The BuildCraft Wrench is a new tool to reorient machines and piping systems.