Penetrant (mechanical, electrical, or structural)

Penetrant is a kind of material that can go through things, like mechanical, electrical or structural material. Mechanical penetrants are things like screws and nails that can go through something like wood or metal. Electrical penetrants are things like electrical wires that can go through a wall or underground to allow electricity to travel through. Structural penetrants are things like cement or steel beams that can go through a wall or a building to hold it up.