This pre-assembled DC motor was designed for students to learn about electromagnetic forces. The open structure resembles the diagram found in most textbooks. Polarity of the magnets can be reversed to change the direction of rotation. Can also be used with a rheostat to observe the change of speed with the change of current. Can stand vertically or horizontally for best view. Can operate on a 1.5V battery. Comes in a sturdy plastic storage case. Also comes complete with a student activity manual.