Very strong super magnet cylinder with outer diameter of 0.25 inch and thickness (height) of 0.25 inch.

A neodymium magnet (a special type of rare-earth magnet) is a powerful magnet made of a combination of neodymium, iron, and boron — Nd₂Fe₁₄B. These magnets are very strong in comparison to their mass, but are also mechanically fragile and lose their magnetism at temperatures above 80 degrees Celsius. Neodymium magnets are graded in strength from N24 to the strongest N48.