IDEAL FOR DISPLAYS. These discreet, ferrite hook magnets are great value for money and ideal for hanging signs and decorations from a steel ceiling and are commonly used in shops to suspend advertising signs. STRONG MAGNETIC HOLD. Each magnet can support a steel weight of up to 7.3kg vertically from the magnetic face when in flush contact with a mild steel surface of equal thickness. SPECIFICATIONS. 32mm diameter x 38mm high. The internal diameter of the hook is 4mm and is 18mm from the tip of its thread to top.