a more recent development is the electric action which uses low voltage dc to control the key and/or stop mechanisms. electricity may control the action indirectly through air pressure valves (pneumatics), in which case the action is electro-pneumatic. in such actions, an electromagnet attracts a small pilot valve which lets wind go to a bellows ("pneumatic") which opens the pallet. when electricity operates the action directly without the assistance of pneumatics, it is commonly referred to as direct electric action. in this type, the electromagnet's armature carries a disc pallet.