Master Magnetics 3 lb. Pull Alnico Horseshoe Magnet with Keeper is a powerful magnet made of alnico, a permanent magnet alloy of aluminum, nickel, and cobalt, and has a red finish. The magnet has a maximum pull capacity of 3 pounds and comes with a keeper to protect the magnet when it is not in use. This magnet is ideal for school experiments and makes a great gift.