Two Sided Magnet has strong magnetic attraction on both sides. One side of the magnet has a chalkboard like surface and the other side is glosy white dry erase for use with write on, wipe off dry erase markers. The material is great in classrooms or where ever you need the ability to flip the magnet between uses. Medium material is 0.030 inches, suitable for most uses. Thickness is about the same as a dime. This is the thickness used for magnetic car signs.