Description: This item is easy to use, just place the card on the surface of the magnetic material, and it will reveal a magnetic field of pattern. Great for personal or scientific research and it help us study magnetic fields that we can't see. It can be used for quality control, product demonstration, reverse engineering, authentication and educational purposes. Compact and portable size, lightweight, convenient to carry with you. Wonderful educational tool to stimulate our interest in science. Features: Can be used for quality control, product demonstration, reverse engineering, authentication and educational purposes Just place the card on the surface of the magnetic material, and it will reveal a magnetic field of pattern, easy to use Great for personal or scientific research and help us study magnetic fields that we can't see Wonderful educational tool to stimulate our interest in science Compact and portable size, lightweight, convenient to carry with you Specification: Condition: 100% Brand New Color: Dark Green Product Size: Approx. 50 * 50mm / 2.0 * 2.0inch Product Weight: Approx. 1g Package Included: 1 * Magnetic Field Viewer Card