4 x 4 Inch Magnetic Field Viewing Film, Magnetic Field Viewer, Magnetic Flux Display, Magnet Pattern Detector, See Magnetic Field for Scientific Project (4 * 4 Inch)

I used it to visualize the magnetic fields of guitar pickups. Some of them have cover and are sealed so this helps me to see the real construction behind (blades, screws etc.) Also it gives very general idea of the field strength which is nice and of course is represented visually.

This magnetic field viewing film performed exactly as I needed—clearly showing the magnetic field pattern of a camshaft sensor’s target magnet so I could confirm it was functioning properly without wasting money on unnecessary parts. The detail it reveals made diagnosis quick and confident. Beyond that single repair, it’s become a fascinating tool for exploring magnets in everyday items and seeing how their fields are arranged. The film is reusable, easy to handle, and has already provided more value than I expected—both for practical troubleshooting and satisfying my curiosity.

Works great but I would recommend taking it out of the cardboard thing it comes in

I got this to use in a classroom. It's not very sturdy so probably won't last long. It's really neat to see the patterns from the magnets. I haven't found a magnet to make the patterns in the photos yet.

Have you seen what different magnet fields look like? This is a great buy to help visualize what is happening.

Not as flexible as I had hoped but it works great for seeing cracks in tone wheels on camshaft or crankshaft tone wheels

Works fine. No issues.

I have been using the green field viewer sheets for years, and they are great, but I was looking for something that made a clearer image. So I got some of these. And they are amazing! I thought they'd be good, given the reviews, but I assumed that the photos were faked. They aren't—you really do get different colors and a very striking pattern when you have an interesting magnetic field to make visible. The only downside is this: This film only works on really strong fields. Refrigerator magnets.... Nope. You need strong rare earth magnets to see a good effect. But if you have strong magnets and you need to make a striking visualization of their field.... This is a great tool for the job!