Where can I find a magnetic field visualize vellum?

Question

A show on the History Channel about magnets had a scene where vellum of two clear sheets of plastic sandwiched a material that showed the magnet field lines when placed on a magnet.

I want some. Where can I find it?

Answer 1

Favorite Answer

http://www.arborsci.com/detail.aspx?ID=639 - Arbor Scientific has one for $2.95 at credit card size, or bigger sheets for $19 (http://www.arborsci.com/detail.aspx?ID=640).