An oak lever can be built in the Lever space of the Throne Room in a player-owned house. It requires 68 Construction to build and when built, it gives 300 experience. The player must have a hammer and a saw in their inventory to build it.
It is used to operate the trap in your throne room (if there is one), and also controls challenge mode in the Dungeon. Left clicking on the lever will activate the trap in the throne room, while right clicking on the lever gives you the option to activate challenge or PvP challenge mode. The challenge or PvP challenge mode will end if you right click on the lever again. If you do not have a fiendish mechanism to activate, then the lever is useless on the trap.