This is just the magnet piece only that separates from the back of the button. It is a small metal plate 1" x 0.5" with 2 small neodymium magnets attached to the plate. These clothing/shirt magnets recommended for use with 1.5" or larger buttons with a metal backing. These can also be used to convert pinback buttons into magnetic buttons giving people the option to use either the pin or use the magnet so a hole does not get poked into a person's clothes.
This product contains strong magnets which can be dangerous to children, people with pacemakers, electronics, and magnetic media. Full product warning can be found here.
Small parts, keep away from children.
This product contains nickel which is a known allergen. The detachable magnetic bar is made of nickel plated steel. If you are allergic to nickel avoid contact with this component.