Magnetic force line display device using a large number of black cylindrical compass sticks when induced by a magnetic force that comes close Will be able to clearly show lines of force or magnetic fields, consisting of

1. Rectangular plastic frame with a stand height from the floor, size about 24.7x25.4 cm, can arrange at least 3 compass packing sheets.
2. The compass packing sheet is a transparent plastic sheet that contains a cylindrical compass in a black circle. At the edges there are joints similar to jigsaws. Can be joined together with several sheets, size approx. 8.5x24.2 cm. There are at least 3 sheets in the set.
3. U-shaped magnet and square bar magnet There is a symbol or color showing the north-south pole, clear, unbreakable.