Pack of 10032mm diameter x 7mm thick with a 5mm diameter countersunk hole for fixingEach magnet is only magnetic on the countersunk faceEach magnet can support 6.9kg pull vertically from the magnetic face when in flush contact with a mild steel surface of equal thicknessChrome coated steel shellCan be fixed in place with 5mm diameter countersunk screwsOutstanding value for money, these ferrite pot magnets are made of a ferrite magnet sunken in to a steel shell meaning that the north pole is on the centre of the magnetic face and the south pole is on the outer edge around it. The steel pot increases the adhesive force of the magnets giving them a strong hold for their size. An added advantage of pot magnets is that they are resistant to chipping or cracking following constant impact with a steel surface.