1PCS 25/30/50mm Magnetic Field Viewing Film Field Viewer Pattern Display Membrane Magnetic Card Detector Educational Tool Features: This project is easy to use. Place the card on the magnetic material to display the patterned magnetic field. Great for personal or scientific research. It can help us study magnetic fields that are invisible to the naked eye. It can be used for quality control, product demonstration, reverse engineering, certification and educational purposes. Small and portable, lightweight and easy to carry. This is a great educational tool to stimulate our interest in science. The magnetic field observer is an encapsulation film that allows users to observe static magnetic fields. This highly flexible film is suitable for any convex or concave magnetic materials. Specifications: Part Name: Magnetic Field Observer Size: 5050mm 2525mm 3030mm Color: Yellow Effect: True Color, Gray Material: ABS Quantity: 1 piece Package Contents: 1 Magnetic Field Observer Note: Please allow 1-2 cm error due to manual measurement. Please confirm that you do not mind before placing an order. Due to differences between different monitors, the picture may not reflect the actual color of the item. Thank you! _x000D_