Learning Resources Primary Science Mighty Magnets (Set of 12). These brightly coloured horseshoe-shaped magnets are made of durable plastic, perfect for young scientists. Magnets are magnetically correct: one foot north, one south. Set includes 12 horseshoe magnets in six different colours; yellow, pink, red, green, blue and orange. Magnets measure 12.5cm H. Set of 12 magnets. Suitable for ages 3+