Large Ferrite Block Magnet with red and blue poles, stamped with ‘N’ & ‘S’. Ferrite magnets exhibit a high degree of coercive strength, making them more resistant to demagnetisation. Large surface area that is magnetic in dependable ferrite material. Magnets are great for highlighting the effect of attraction and repulsion. Also use magnets to investigate things like what is magnetic and what is not. Size: 1.4 x 1 x 5cm in a set of 30.