Used as a middle school physics force line to the electric field in the field of the size and direction of the image to express.Products is composed of five pieces of electric field line demonstration board, respectively for single point electrode demo board, two point electrodes demo board, parallel plate electrode demo board, an annular electrode demo board, pointed conductor demo board. The demonstration board adopts the "372" material with good transparency. The shape and size of the five demonstration boards are 108 * 90 * 6.5mm.